diff --git a/include/lib/libc/aarch32/float.h b/include/lib/libc/aarch32/float.h
new file mode 100644
index 0000000..857d76e
--- /dev/null
+++ b/include/lib/libc/aarch32/float.h
@@ -0,0 +1,100 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 1989 Regents of the University of California.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	from: @(#)float.h	7.1 (Berkeley) 5/8/90
+ * $FreeBSD$
+ */
+
+#ifndef _MACHINE_FLOAT_H_
+#define _MACHINE_FLOAT_H_ 1
+
+#include <sys/cdefs.h>
+
+__BEGIN_DECLS
+extern int __flt_rounds(void);
+__END_DECLS
+
+#define FLT_RADIX	2		/* b */
+#ifndef	_ARM_HARD_FLOAT
+#define	FLT_ROUNDS	__flt_rounds()
+#else
+#define	FLT_ROUNDS	(-1)
+#endif
+#if __ISO_C_VISIBLE >= 1999
+#define	FLT_EVAL_METHOD	0
+#define	DECIMAL_DIG	17		/* max precision in decimal digits */
+#endif
+
+#define FLT_MANT_DIG	24		/* p */
+#define FLT_EPSILON	1.19209290E-07F	/* b**(1-p) */
+#define FLT_DIG		6		/* floor((p-1)*log10(b))+(b == 10) */
+#define FLT_MIN_EXP	(-125)		/* emin */
+#define FLT_MIN		1.17549435E-38F	/* b**(emin-1) */
+#define FLT_MIN_10_EXP	(-37)		/* ceil(log10(b**(emin-1))) */
+#define FLT_MAX_EXP	128		/* emax */
+#define FLT_MAX		3.40282347E+38F	/* (1-b**(-p))*b**emax */
+#define FLT_MAX_10_EXP	38		/* floor(log10((1-b**(-p))*b**emax)) */
+#if __ISO_C_VISIBLE >= 2011
+#define	FLT_TRUE_MIN	1.40129846E-45F	/* b**(emin-p) */
+#define	FLT_DECIMAL_DIG	9		/* ceil(1+p*log10(b)) */
+#define	FLT_HAS_SUBNORM	1
+#endif /* __ISO_C_VISIBLE >= 2011 */
+
+#define DBL_MANT_DIG	53
+#define DBL_EPSILON	2.2204460492503131E-16
+#define DBL_DIG		15
+#define DBL_MIN_EXP	(-1021)
+#define DBL_MIN		2.2250738585072014E-308
+#define DBL_MIN_10_EXP	(-307)
+#define DBL_MAX_EXP	1024
+#define DBL_MAX		1.7976931348623157E+308
+#define DBL_MAX_10_EXP	308
+#if __ISO_C_VISIBLE >= 2011
+#define	DBL_TRUE_MIN	4.9406564584124654E-324
+#define	DBL_DECIMAL_DIG	17
+#define	DBL_HAS_SUBNORM	1
+#endif /* __ISO_C_VISIBLE >= 2011 */
+
+#define LDBL_MANT_DIG	DBL_MANT_DIG
+#define LDBL_EPSILON	((long double)DBL_EPSILON)
+#define LDBL_DIG	DBL_DIG
+#define LDBL_MIN_EXP	DBL_MIN_EXP
+#define LDBL_MIN	((long double)DBL_MIN)
+#define LDBL_MIN_10_EXP	DBL_MIN_10_EXP
+#define LDBL_MAX_EXP	DBL_MAX_EXP
+#define LDBL_MAX	((long double)DBL_MAX)
+#define LDBL_MAX_10_EXP	DBL_MAX_10_EXP
+#if __ISO_C_VISIBLE >= 2011
+#define	LDBL_TRUE_MIN	((long double)DBL_TRUE_MIN)
+#define	LDBL_DECIMAL_DIG DBL_DECIMAL_DIG
+#define	LDBL_HAS_SUBNORM DBL_HAS_SUBNORM
+#endif /* __ISO_C_VISIBLE >= 2011 */
+
+#endif /* _MACHINE_FLOAT_H_ */
diff --git a/include/lib/libc/aarch64/float.h b/include/lib/libc/aarch64/float.h
new file mode 100644
index 0000000..0829f6f
--- /dev/null
+++ b/include/lib/libc/aarch64/float.h
@@ -0,0 +1,94 @@
+/*-
+ * Copyright (c) 1989 Regents of the University of California.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	from: @(#)float.h	7.1 (Berkeley) 5/8/90
+ * $FreeBSD$
+ */
+
+#ifndef _MACHINE_FLOAT_H_
+#define	_MACHINE_FLOAT_H_
+
+#include <sys/cdefs.h>
+
+__BEGIN_DECLS
+extern int __flt_rounds(void);
+__END_DECLS
+
+#define	FLT_RADIX	2		/* b */
+#define	FLT_ROUNDS	__flt_rounds()
+#if __ISO_C_VISIBLE >= 1999
+#define	FLT_EVAL_METHOD	0
+#define	DECIMAL_DIG	17		/* max precision in decimal digits */
+#endif
+
+#define	FLT_MANT_DIG	24		/* p */
+#define	FLT_EPSILON	1.19209290E-07F	/* b**(1-p) */
+#define	FLT_DIG		6		/* floor((p-1)*log10(b))+(b == 10) */
+#define	FLT_MIN_EXP	(-125)		/* emin */
+#define	FLT_MIN		1.17549435E-38F	/* b**(emin-1) */
+#define	FLT_MIN_10_EXP	(-37)		/* ceil(log10(b**(emin-1))) */
+#define	FLT_MAX_EXP	128		/* emax */
+#define	FLT_MAX		3.40282347E+38F	/* (1-b**(-p))*b**emax */
+#define	FLT_MAX_10_EXP	38		/* floor(log10((1-b**(-p))*b**emax)) */
+#if __ISO_C_VISIBLE >= 2011
+#define	FLT_TRUE_MIN	1.40129846E-45F	/* b**(emin-p) */
+#define	FLT_DECIMAL_DIG	9		/* ceil(1+p*log10(b)) */
+#define	FLT_HAS_SUBNORM	1
+#endif /* __ISO_C_VISIBLE >= 2011 */
+
+#define	DBL_MANT_DIG	53
+#define	DBL_EPSILON	2.2204460492503131E-16
+#define	DBL_DIG		15
+#define	DBL_MIN_EXP	(-1021)
+#define	DBL_MIN		2.2250738585072014E-308
+#define	DBL_MIN_10_EXP	(-307)
+#define	DBL_MAX_EXP	1024
+#define	DBL_MAX		1.7976931348623157E+308
+#define	DBL_MAX_10_EXP	308
+#if __ISO_C_VISIBLE >= 2011
+#define	DBL_TRUE_MIN	4.9406564584124654E-324
+#define	DBL_DECIMAL_DIG	17
+#define	DBL_HAS_SUBNORM	1
+#endif /* __ISO_C_VISIBLE >= 2011 */
+
+#define	LDBL_MANT_DIG	113
+#define	LDBL_EPSILON	1.925929944387235853055977942584927319E-34L
+#define	LDBL_DIG	33
+#define	LDBL_MIN_EXP	(-16381)
+#define	LDBL_MIN	3.362103143112093506262677817321752603E-4932L
+#define	LDBL_MIN_10_EXP	(-4931)
+#define	LDBL_MAX_EXP	(+16384)
+#define	LDBL_MAX	1.189731495357231765085759326628007016E+4932L
+#define	LDBL_MAX_10_EXP	(+4932)
+#if __ISO_C_VISIBLE >= 2011
+#define	LDBL_TRUE_MIN	6.475175119438025110924438958227646552E-4966L
+#define	LDBL_DECIMAL_DIG 36
+#define	LDBL_HAS_SUBNORM 1
+#endif /* __ISO_C_VISIBLE >= 2011 */
+
+#endif /* _MACHINE_FLOAT_H_ */
diff --git a/include/lib/libc/sys/cdefs.h b/include/lib/libc/sys/cdefs.h
new file mode 100644
index 0000000..1ace5fb
--- /dev/null
+++ b/include/lib/libc/sys/cdefs.h
@@ -0,0 +1,922 @@
+/*-
+ * SPDX-License-Identifier: BSD-3-Clause
+ *
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Berkeley Software Design, Inc.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)cdefs.h	8.8 (Berkeley) 1/9/95
+ * $FreeBSD$
+ */
+
+#ifndef	_SYS_CDEFS_H_
+#define	_SYS_CDEFS_H_
+
+#if defined(_KERNEL) && defined(_STANDALONE)
+#error "_KERNEL and _STANDALONE are mutually exclusive"
+#endif
+
+/*
+ * Testing against Clang-specific extensions.
+ */
+#ifndef	__has_attribute
+#define	__has_attribute(x)	0
+#endif
+#ifndef	__has_extension
+#define	__has_extension		__has_feature
+#endif
+#ifndef	__has_feature
+#define	__has_feature(x)	0
+#endif
+#ifndef	__has_include
+#define	__has_include(x)	0
+#endif
+#ifndef	__has_builtin
+#define	__has_builtin(x)	0
+#endif
+
+#if defined(__cplusplus)
+#define	__BEGIN_DECLS	extern "C" {
+#define	__END_DECLS	}
+#else
+#define	__BEGIN_DECLS
+#define	__END_DECLS
+#endif
+
+/*
+ * This code has been put in place to help reduce the addition of
+ * compiler specific defines in FreeBSD code.  It helps to aid in
+ * having a compiler-agnostic source tree.
+ */
+
+#if defined(__GNUC__)
+
+#if __GNUC__ >= 3
+#define	__GNUCLIKE_ASM 3
+#define	__GNUCLIKE_MATH_BUILTIN_CONSTANTS
+#else
+#define	__GNUCLIKE_ASM 2
+#endif
+#define	__GNUCLIKE___TYPEOF 1
+#define	__GNUCLIKE___SECTION 1
+
+#define	__GNUCLIKE_CTOR_SECTION_HANDLING 1
+
+#define	__GNUCLIKE_BUILTIN_CONSTANT_P 1
+
+#if (__GNUC_MINOR__ > 95 || __GNUC__ >= 3)
+#define	__GNUCLIKE_BUILTIN_VARARGS 1
+#define	__GNUCLIKE_BUILTIN_STDARG 1
+#define	__GNUCLIKE_BUILTIN_VAALIST 1
+#endif
+
+#define	__GNUC_VA_LIST_COMPATIBILITY 1
+
+/*
+ * Compiler memory barriers, specific to gcc and clang.
+ */
+#define	__compiler_membar()	__asm __volatile(" " : : : "memory")
+
+#define	__GNUCLIKE_BUILTIN_NEXT_ARG 1
+#define	__GNUCLIKE_MATH_BUILTIN_RELOPS
+
+#define	__GNUCLIKE_BUILTIN_MEMCPY 1
+
+/* XXX: if __GNUC__ >= 2: not tested everywhere originally, where replaced */
+#define	__CC_SUPPORTS_INLINE 1
+#define	__CC_SUPPORTS___INLINE 1
+#define	__CC_SUPPORTS___INLINE__ 1
+
+#define	__CC_SUPPORTS___FUNC__ 1
+#define	__CC_SUPPORTS_WARNING 1
+
+#define	__CC_SUPPORTS_VARADIC_XXX 1 /* see varargs.h */
+
+#define	__CC_SUPPORTS_DYNAMIC_ARRAY_INIT 1
+
+#endif /* __GNUC__ */
+
+/*
+ * Macro to test if we're using a specific version of gcc or later.
+ */
+#if defined(__GNUC__)
+#define	__GNUC_PREREQ__(ma, mi)	\
+	(__GNUC__ > (ma) || __GNUC__ == (ma) && __GNUC_MINOR__ >= (mi))
+#else
+#define	__GNUC_PREREQ__(ma, mi)	0
+#endif
+
+/*
+ * The __CONCAT macro is used to concatenate parts of symbol names, e.g.
+ * with "#define OLD(foo) __CONCAT(old,foo)", OLD(foo) produces oldfoo.
+ * The __CONCAT macro is a bit tricky to use if it must work in non-ANSI
+ * mode -- there must be no spaces between its arguments, and for nested
+ * __CONCAT's, all the __CONCAT's must be at the left.  __CONCAT can also
+ * concatenate double-quoted strings produced by the __STRING macro, but
+ * this only works with ANSI C.
+ *
+ * __XSTRING is like __STRING, but it expands any macros in its argument
+ * first.  It is only available with ANSI C.
+ */
+#if defined(__STDC__) || defined(__cplusplus)
+#define	__P(protos)	protos		/* full-blown ANSI C */
+#define	__CONCAT1(x,y)	x ## y
+#define	__CONCAT(x,y)	__CONCAT1(x,y)
+#define	__STRING(x)	#x		/* stringify without expanding x */
+#define	__XSTRING(x)	__STRING(x)	/* expand x, then stringify */
+
+#define	__const		const		/* define reserved names to standard */
+#define	__signed	signed
+#define	__volatile	volatile
+#if defined(__cplusplus)
+#define	__inline	inline		/* convert to C++ keyword */
+#else
+#if !(defined(__CC_SUPPORTS___INLINE))
+#define	__inline			/* delete GCC keyword */
+#endif /* ! __CC_SUPPORTS___INLINE */
+#endif /* !__cplusplus */
+
+#else	/* !(__STDC__ || __cplusplus) */
+#define	__P(protos)	()		/* traditional C preprocessor */
+#define	__CONCAT(x,y)	x/**/y
+#define	__STRING(x)	"x"
+
+#if !defined(__CC_SUPPORTS___INLINE)
+#define	__const				/* delete pseudo-ANSI C keywords */
+#define	__inline
+#define	__signed
+#define	__volatile
+/*
+ * In non-ANSI C environments, new programs will want ANSI-only C keywords
+ * deleted from the program and old programs will want them left alone.
+ * When using a compiler other than gcc, programs using the ANSI C keywords
+ * const, inline etc. as normal identifiers should define -DNO_ANSI_KEYWORDS.
+ * When using "gcc -traditional", we assume that this is the intent; if
+ * __GNUC__ is defined but __STDC__ is not, we leave the new keywords alone.
+ */
+#ifndef	NO_ANSI_KEYWORDS
+#define	const				/* delete ANSI C keywords */
+#define	inline
+#define	signed
+#define	volatile
+#endif	/* !NO_ANSI_KEYWORDS */
+#endif	/* !__CC_SUPPORTS___INLINE */
+#endif	/* !(__STDC__ || __cplusplus) */
+
+/*
+ * Compiler-dependent macros to help declare dead (non-returning) and
+ * pure (no side effects) functions, and unused variables.  They are
+ * null except for versions of gcc that are known to support the features
+ * properly (old versions of gcc-2 supported the dead and pure features
+ * in a different (wrong) way).  If we do not provide an implementation
+ * for a given compiler, let the compile fail if it is told to use
+ * a feature that we cannot live without.
+ */
+#define	__weak_symbol	__attribute__((__weak__))
+#if !__GNUC_PREREQ__(2, 5)
+#define	__dead2
+#define	__pure2
+#define	__unused
+#endif
+#if __GNUC__ == 2 && __GNUC_MINOR__ >= 5 && __GNUC_MINOR__ < 7
+#define	__dead2		__attribute__((__noreturn__))
+#define	__pure2		__attribute__((__const__))
+#define	__unused
+/* XXX Find out what to do for __packed, __aligned and __section */
+#endif
+#if __GNUC_PREREQ__(2, 7)
+#define	__dead2		__attribute__((__noreturn__))
+#define	__pure2		__attribute__((__const__))
+#define	__unused	__attribute__((__unused__))
+#define	__used		__attribute__((__used__))
+#define	__packed	__attribute__((__packed__))
+#define	__aligned(x)	__attribute__((__aligned__(x)))
+#define	__section(x)	__attribute__((__section__(x)))
+#endif
+#if __GNUC_PREREQ__(4, 3) || __has_attribute(__alloc_size__)
+#define	__alloc_size(x)	__attribute__((__alloc_size__(x)))
+#define	__alloc_size2(n, x)	__attribute__((__alloc_size__(n, x)))
+#else
+#define	__alloc_size(x)
+#define	__alloc_size2(n, x)
+#endif
+#if __GNUC_PREREQ__(4, 9) || __has_attribute(__alloc_align__)
+#define	__alloc_align(x)	__attribute__((__alloc_align__(x)))
+#else
+#define	__alloc_align(x)
+#endif
+
+#if !__GNUC_PREREQ__(2, 95)
+#define	__alignof(x)	__offsetof(struct { char __a; x __b; }, __b)
+#endif
+
+/*
+ * Keywords added in C11.
+ */
+
+#if !defined(__STDC_VERSION__) || __STDC_VERSION__ < 201112L
+
+#if !__has_extension(c_alignas)
+#if (defined(__cplusplus) && __cplusplus >= 201103L) || \
+    __has_extension(cxx_alignas)
+#define	_Alignas(x)		alignas(x)
+#else
+/* XXX: Only emulates _Alignas(constant-expression); not _Alignas(type-name). */
+#define	_Alignas(x)		__aligned(x)
+#endif
+#endif
+
+#if defined(__cplusplus) && __cplusplus >= 201103L
+#define	_Alignof(x)		alignof(x)
+#else
+#define	_Alignof(x)		__alignof(x)
+#endif
+
+#if !defined(__cplusplus) && !__has_extension(c_atomic) && \
+	!__has_extension(cxx_atomic) && !__GNUC_PREREQ__(4, 7)
+/*
+ * No native support for _Atomic(). Place object in structure to prevent
+ * most forms of direct non-atomic access.
+ */
+#define	_Atomic(T)		struct { T volatile __val; }
+#endif
+
+#if defined(__cplusplus) && __cplusplus >= 201103L
+#define	_Noreturn		[[noreturn]]
+#else
+#define	_Noreturn		__dead2
+#endif
+
+#if !__has_extension(c_static_assert)
+#if (defined(__cplusplus) && __cplusplus >= 201103L) || \
+    __has_extension(cxx_static_assert)
+#define	_Static_assert(x, y)	static_assert(x, y)
+#elif __GNUC_PREREQ__(4,6) && !defined(__cplusplus)
+/* Nothing, gcc 4.6 and higher has _Static_assert built-in */
+#elif defined(__COUNTER__)
+#define	_Static_assert(x, y)	__Static_assert(x, __COUNTER__)
+#define	__Static_assert(x, y)	___Static_assert(x, y)
+#define	___Static_assert(x, y)	typedef char __assert_ ## y[(x) ? 1 : -1] \
+				__unused
+#else
+#define	_Static_assert(x, y)	struct __hack
+#endif
+#endif
+
+#if !__has_extension(c_thread_local)
+/*
+ * XXX: Some compilers (Clang 3.3, GCC 4.7) falsely announce C++11 mode
+ * without actually supporting the thread_local keyword. Don't check for
+ * the presence of C++11 when defining _Thread_local.
+ */
+#if /* (defined(__cplusplus) && __cplusplus >= 201103L) || */ \
+    __has_extension(cxx_thread_local)
+#define	_Thread_local		thread_local
+#else
+#define	_Thread_local		__thread
+#endif
+#endif
+
+#endif /* __STDC_VERSION__ || __STDC_VERSION__ < 201112L */
+
+/*
+ * Emulation of C11 _Generic().  Unlike the previously defined C11
+ * keywords, it is not possible to implement this using exactly the same
+ * syntax.  Therefore implement something similar under the name
+ * __generic().  Unlike _Generic(), this macro can only distinguish
+ * between a single type, so it requires nested invocations to
+ * distinguish multiple cases.
+ */
+
+#if (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L) || \
+    __has_extension(c_generic_selections)
+#define	__generic(expr, t, yes, no)					\
+	_Generic(expr, t: yes, default: no)
+#elif __GNUC_PREREQ__(3, 1) && !defined(__cplusplus)
+#define	__generic(expr, t, yes, no)					\
+	__builtin_choose_expr(						\
+	    __builtin_types_compatible_p(__typeof(expr), t), yes, no)
+#endif
+
+/*
+ * C99 Static array indices in function parameter declarations.  Syntax such as:
+ * void bar(int myArray[static 10]);
+ * is allowed in C99 but not in C++.  Define __min_size appropriately so
+ * headers using it can be compiled in either language.  Use like this:
+ * void bar(int myArray[__min_size(10)]);
+ */
+#if !defined(__cplusplus) && \
+    (defined(__clang__) || __GNUC_PREREQ__(4, 6)) && \
+    (!defined(__STDC_VERSION__) || (__STDC_VERSION__ >= 199901))
+#define __min_size(x)	static (x)
+#else
+#define __min_size(x)	(x)
+#endif
+
+#if __GNUC_PREREQ__(2, 96)
+#define	__malloc_like	__attribute__((__malloc__))
+#define	__pure		__attribute__((__pure__))
+#else
+#define	__malloc_like
+#define	__pure
+#endif
+
+#if __GNUC_PREREQ__(3, 1)
+#define	__always_inline	__attribute__((__always_inline__))
+#else
+#define	__always_inline
+#endif
+
+#if __GNUC_PREREQ__(3, 1)
+#define	__noinline	__attribute__ ((__noinline__))
+#else
+#define	__noinline
+#endif
+
+#if __GNUC_PREREQ__(3, 4)
+#define	__fastcall	__attribute__((__fastcall__))
+#define	__result_use_check	__attribute__((__warn_unused_result__))
+#else
+#define	__fastcall
+#define	__result_use_check
+#endif
+
+#if __GNUC_PREREQ__(4, 1)
+#define	__returns_twice	__attribute__((__returns_twice__))
+#else
+#define	__returns_twice
+#endif
+
+#if __GNUC_PREREQ__(4, 6) || __has_builtin(__builtin_unreachable)
+#define	__unreachable()	__builtin_unreachable()
+#else
+#define	__unreachable()	((void)0)
+#endif
+
+/* XXX: should use `#if __STDC_VERSION__ < 199901'. */
+#if !__GNUC_PREREQ__(2, 7)
+#define	__func__	NULL
+#endif
+
+#if (defined(__GNUC__) && __GNUC__ >= 2) && !defined(__STRICT_ANSI__) || __STDC_VERSION__ >= 199901
+#define	__LONG_LONG_SUPPORTED
+#endif
+
+/* C++11 exposes a load of C99 stuff */
+#if defined(__cplusplus) && __cplusplus >= 201103L
+#define	__LONG_LONG_SUPPORTED
+#ifndef	__STDC_LIMIT_MACROS
+#define	__STDC_LIMIT_MACROS
+#endif
+#ifndef	__STDC_CONSTANT_MACROS
+#define	__STDC_CONSTANT_MACROS
+#endif
+#endif
+
+/*
+ * GCC 2.95 provides `__restrict' as an extension to C90 to support the
+ * C99-specific `restrict' type qualifier.  We happen to use `__restrict' as
+ * a way to define the `restrict' type qualifier without disturbing older
+ * software that is unaware of C99 keywords.
+ */
+#if !(__GNUC__ == 2 && __GNUC_MINOR__ == 95)
+#if !defined(__STDC_VERSION__) || __STDC_VERSION__ < 199901
+#define	__restrict
+#else
+#define	__restrict	restrict
+#endif
+#endif
+
+/*
+ * GNU C version 2.96 adds explicit branch prediction so that
+ * the CPU back-end can hint the processor and also so that
+ * code blocks can be reordered such that the predicted path
+ * sees a more linear flow, thus improving cache behavior, etc.
+ *
+ * The following two macros provide us with a way to utilize this
+ * compiler feature.  Use __predict_true() if you expect the expression
+ * to evaluate to true, and __predict_false() if you expect the
+ * expression to evaluate to false.
+ *
+ * A few notes about usage:
+ *
+ *	* Generally, __predict_false() error condition checks (unless
+ *	  you have some _strong_ reason to do otherwise, in which case
+ *	  document it), and/or __predict_true() `no-error' condition
+ *	  checks, assuming you want to optimize for the no-error case.
+ *
+ *	* Other than that, if you don't know the likelihood of a test
+ *	  succeeding from empirical or other `hard' evidence, don't
+ *	  make predictions.
+ *
+ *	* These are meant to be used in places that are run `a lot'.
+ *	  It is wasteful to make predictions in code that is run
+ *	  seldomly (e.g. at subsystem initialization time) as the
+ *	  basic block reordering that this affects can often generate
+ *	  larger code.
+ */
+#if __GNUC_PREREQ__(2, 96)
+#define	__predict_true(exp)     __builtin_expect((exp), 1)
+#define	__predict_false(exp)    __builtin_expect((exp), 0)
+#else
+#define	__predict_true(exp)     (exp)
+#define	__predict_false(exp)    (exp)
+#endif
+
+#if __GNUC_PREREQ__(4, 0)
+#define	__null_sentinel	__attribute__((__sentinel__))
+#define	__exported	__attribute__((__visibility__("default")))
+#define	__hidden	__attribute__((__visibility__("hidden")))
+#else
+#define	__null_sentinel
+#define	__exported
+#define	__hidden
+#endif
+
+/*
+ * We define this here since <stddef.h>, <sys/queue.h>, and <sys/types.h>
+ * require it.
+ */
+#if __GNUC_PREREQ__(4, 1)
+#define	__offsetof(type, field)	 __builtin_offsetof(type, field)
+#else
+#ifndef __cplusplus
+#define	__offsetof(type, field) \
+	((__size_t)(__uintptr_t)((const volatile void *)&((type *)0)->field))
+#else
+#define	__offsetof(type, field)					\
+  (__offsetof__ (reinterpret_cast <__size_t>			\
+                 (&reinterpret_cast <const volatile char &>	\
+                  (static_cast<type *> (0)->field))))
+#endif
+#endif
+#define	__rangeof(type, start, end) \
+	(__offsetof(type, end) - __offsetof(type, start))
+
+/*
+ * Given the pointer x to the member m of the struct s, return
+ * a pointer to the containing structure.  When using GCC, we first
+ * assign pointer x to a local variable, to check that its type is
+ * compatible with member m.
+ */
+#if __GNUC_PREREQ__(3, 1)
+#define	__containerof(x, s, m) ({					\
+	const volatile __typeof(((s *)0)->m) *__x = (x);		\
+	__DEQUALIFY(s *, (const volatile char *)__x - __offsetof(s, m));\
+})
+#else
+#define	__containerof(x, s, m)						\
+	__DEQUALIFY(s *, (const volatile char *)(x) - __offsetof(s, m))
+#endif
+
+/*
+ * Compiler-dependent macros to declare that functions take printf-like
+ * or scanf-like arguments.  They are null except for versions of gcc
+ * that are known to support the features properly (old versions of gcc-2
+ * didn't permit keeping the keywords out of the application namespace).
+ */
+#if !__GNUC_PREREQ__(2, 7)
+#define	__printflike(fmtarg, firstvararg)
+#define	__scanflike(fmtarg, firstvararg)
+#define	__format_arg(fmtarg)
+#define	__strfmonlike(fmtarg, firstvararg)
+#define	__strftimelike(fmtarg, firstvararg)
+#else
+#define	__printflike(fmtarg, firstvararg) \
+	    __attribute__((__format__ (__printf__, fmtarg, firstvararg)))
+#define	__scanflike(fmtarg, firstvararg) \
+	    __attribute__((__format__ (__scanf__, fmtarg, firstvararg)))
+#define	__format_arg(fmtarg)	__attribute__((__format_arg__ (fmtarg)))
+#define	__strfmonlike(fmtarg, firstvararg) \
+	    __attribute__((__format__ (__strfmon__, fmtarg, firstvararg)))
+#define	__strftimelike(fmtarg, firstvararg) \
+	    __attribute__((__format__ (__strftime__, fmtarg, firstvararg)))
+#endif
+
+/* Compiler-dependent macros that rely on FreeBSD-specific extensions. */
+#if defined(__FreeBSD_cc_version) && __FreeBSD_cc_version >= 300001 && \
+    defined(__GNUC__)
+#define	__printf0like(fmtarg, firstvararg) \
+	    __attribute__((__format__ (__printf0__, fmtarg, firstvararg)))
+#else
+#define	__printf0like(fmtarg, firstvararg)
+#endif
+
+#if defined(__GNUC__)
+#define	__strong_reference(sym,aliassym)	\
+	extern __typeof (sym) aliassym __attribute__ ((__alias__ (#sym)))
+#ifdef __STDC__
+#define	__weak_reference(sym,alias)	\
+	__asm__(".weak " #alias);	\
+	__asm__(".equ "  #alias ", " #sym)
+#define	__warn_references(sym,msg)	\
+	__asm__(".section .gnu.warning." #sym);	\
+	__asm__(".asciz \"" msg "\"");	\
+	__asm__(".previous")
+#define	__sym_compat(sym,impl,verid)	\
+	__asm__(".symver " #impl ", " #sym "@" #verid)
+#define	__sym_default(sym,impl,verid)	\
+	__asm__(".symver " #impl ", " #sym "@@@" #verid)
+#else
+#define	__weak_reference(sym,alias)	\
+	__asm__(".weak alias");		\
+	__asm__(".equ alias, sym")
+#define	__warn_references(sym,msg)	\
+	__asm__(".section .gnu.warning.sym"); \
+	__asm__(".asciz \"msg\"");	\
+	__asm__(".previous")
+#define	__sym_compat(sym,impl,verid)	\
+	__asm__(".symver impl, sym@verid")
+#define	__sym_default(impl,sym,verid)	\
+	__asm__(".symver impl, sym@@@verid")
+#endif	/* __STDC__ */
+#endif	/* __GNUC__ */
+
+#define	__GLOBL(sym)	__asm__(".globl " __XSTRING(sym))
+#define	__WEAK(sym)	__asm__(".weak " __XSTRING(sym))
+
+#if defined(__GNUC__)
+#define	__IDSTRING(name,string)	__asm__(".ident\t\"" string "\"")
+#else
+/*
+ * The following definition might not work well if used in header files,
+ * but it should be better than nothing.  If you want a "do nothing"
+ * version, then it should generate some harmless declaration, such as:
+ *    #define	__IDSTRING(name,string)	struct __hack
+ */
+#define	__IDSTRING(name,string)	static const char name[] __unused = string
+#endif
+
+/*
+ * Embed the rcs id of a source file in the resulting library.  Note that in
+ * more recent ELF binutils, we use .ident allowing the ID to be stripped.
+ * Usage:
+ *	__FBSDID("$FreeBSD$");
+ */
+#ifndef	__FBSDID
+#if !defined(STRIP_FBSDID)
+#define	__FBSDID(s)	__IDSTRING(__CONCAT(__rcsid_,__LINE__),s)
+#else
+#define	__FBSDID(s)	struct __hack
+#endif
+#endif
+
+#ifndef	__RCSID
+#ifndef	NO__RCSID
+#define	__RCSID(s)	__IDSTRING(__CONCAT(__rcsid_,__LINE__),s)
+#else
+#define	__RCSID(s)	struct __hack
+#endif
+#endif
+
+#ifndef	__RCSID_SOURCE
+#ifndef	NO__RCSID_SOURCE
+#define	__RCSID_SOURCE(s)	__IDSTRING(__CONCAT(__rcsid_source_,__LINE__),s)
+#else
+#define	__RCSID_SOURCE(s)	struct __hack
+#endif
+#endif
+
+#ifndef	__SCCSID
+#ifndef	NO__SCCSID
+#define	__SCCSID(s)	__IDSTRING(__CONCAT(__sccsid_,__LINE__),s)
+#else
+#define	__SCCSID(s)	struct __hack
+#endif
+#endif
+
+#ifndef	__COPYRIGHT
+#ifndef	NO__COPYRIGHT
+#define	__COPYRIGHT(s)	__IDSTRING(__CONCAT(__copyright_,__LINE__),s)
+#else
+#define	__COPYRIGHT(s)	struct __hack
+#endif
+#endif
+
+#ifndef	__DECONST
+#define	__DECONST(type, var)	((type)(__uintptr_t)(const void *)(var))
+#endif
+
+#ifndef	__DEVOLATILE
+#define	__DEVOLATILE(type, var)	((type)(__uintptr_t)(volatile void *)(var))
+#endif
+
+#ifndef	__DEQUALIFY
+#define	__DEQUALIFY(type, var)	((type)(__uintptr_t)(const volatile void *)(var))
+#endif
+
+/*-
+ * The following definitions are an extension of the behavior originally
+ * implemented in <sys/_posix.h>, but with a different level of granularity.
+ * POSIX.1 requires that the macros we test be defined before any standard
+ * header file is included.
+ *
+ * Here's a quick run-down of the versions (and some informal names)
+ *  defined(_POSIX_SOURCE)		1003.1-1988
+ *					encoded as 198808 below
+ *  _POSIX_C_SOURCE == 1		1003.1-1990
+ *					encoded as 199009 below
+ *  _POSIX_C_SOURCE == 2		1003.2-1992 C Language Binding Option
+ *					encoded as 199209 below
+ *  _POSIX_C_SOURCE == 199309		1003.1b-1993
+ *					(1003.1 Issue 4, Single Unix Spec v1, Unix 93)
+ *  _POSIX_C_SOURCE == 199506		1003.1c-1995, 1003.1i-1995,
+ *					and the omnibus ISO/IEC 9945-1: 1996
+ *					(1003.1 Issue 5, Single	Unix Spec v2, Unix 95)
+ *  _POSIX_C_SOURCE == 200112		1003.1-2001 (1003.1 Issue 6, Unix 03)
+ *  _POSIX_C_SOURCE == 200809		1003.1-2008 (1003.1 Issue 7)
+ *					IEEE Std 1003.1-2017 (Rev of 1003.1-2008) is
+ *					1003.1-2008 with two TCs applied with
+ *					_POSIX_C_SOURCE=200809 and _XOPEN_SOURCE=700
+ *
+ * In addition, the X/Open Portability Guide, which is now the Single UNIX
+ * Specification, defines a feature-test macro which indicates the version of
+ * that specification, and which subsumes _POSIX_C_SOURCE.
+ *
+ * Our macros begin with two underscores to avoid namespace screwage.
+ */
+
+/* Deal with IEEE Std. 1003.1-1990, in which _POSIX_C_SOURCE == 1. */
+#if defined(_POSIX_C_SOURCE) && _POSIX_C_SOURCE == 1
+#undef _POSIX_C_SOURCE		/* Probably illegal, but beyond caring now. */
+#define	_POSIX_C_SOURCE		199009
+#endif
+
+/* Deal with IEEE Std. 1003.2-1992, in which _POSIX_C_SOURCE == 2. */
+#if defined(_POSIX_C_SOURCE) && _POSIX_C_SOURCE == 2
+#undef _POSIX_C_SOURCE
+#define	_POSIX_C_SOURCE		199209
+#endif
+
+/* Deal with various X/Open Portability Guides and Single UNIX Spec. */
+#ifdef _XOPEN_SOURCE
+#if _XOPEN_SOURCE - 0 >= 700
+#define	__XSI_VISIBLE		700
+#undef _POSIX_C_SOURCE
+#define	_POSIX_C_SOURCE		200809
+#elif _XOPEN_SOURCE - 0 >= 600
+#define	__XSI_VISIBLE		600
+#undef _POSIX_C_SOURCE
+#define	_POSIX_C_SOURCE		200112
+#elif _XOPEN_SOURCE - 0 >= 500
+#define	__XSI_VISIBLE		500
+#undef _POSIX_C_SOURCE
+#define	_POSIX_C_SOURCE		199506
+#endif
+#endif
+
+/*
+ * Deal with all versions of POSIX.  The ordering relative to the tests above is
+ * important.
+ */
+#if defined(_POSIX_SOURCE) && !defined(_POSIX_C_SOURCE)
+#define	_POSIX_C_SOURCE		198808
+#endif
+#ifdef _POSIX_C_SOURCE
+#if _POSIX_C_SOURCE >= 200809
+#define	__POSIX_VISIBLE		200809
+#define	__ISO_C_VISIBLE		1999
+#elif _POSIX_C_SOURCE >= 200112
+#define	__POSIX_VISIBLE		200112
+#define	__ISO_C_VISIBLE		1999
+#elif _POSIX_C_SOURCE >= 199506
+#define	__POSIX_VISIBLE		199506
+#define	__ISO_C_VISIBLE		1990
+#elif _POSIX_C_SOURCE >= 199309
+#define	__POSIX_VISIBLE		199309
+#define	__ISO_C_VISIBLE		1990
+#elif _POSIX_C_SOURCE >= 199209
+#define	__POSIX_VISIBLE		199209
+#define	__ISO_C_VISIBLE		1990
+#elif _POSIX_C_SOURCE >= 199009
+#define	__POSIX_VISIBLE		199009
+#define	__ISO_C_VISIBLE		1990
+#else
+#define	__POSIX_VISIBLE		198808
+#define	__ISO_C_VISIBLE		0
+#endif /* _POSIX_C_SOURCE */
+/*
+ * Both glibc and OpenBSD enable c11 features when _ISOC11_SOURCE is defined, or
+ * when compiling with -stdc=c11. A strict reading of the standard would suggest
+ * doing it only for the former. However, a strict reading also requires C99
+ * mode only, so building with C11 is already undefined. Follow glibc's and
+ * OpenBSD's lead for this non-standard configuration for maximum compatibility.
+ */
+#if _ISOC11_SOURCE || (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 201112L)
+#undef __ISO_C_VISIBLE
+#define __ISO_C_VISIBLE		2011
+#endif
+#else
+/*-
+ * Deal with _ANSI_SOURCE:
+ * If it is defined, and no other compilation environment is explicitly
+ * requested, then define our internal feature-test macros to zero.  This
+ * makes no difference to the preprocessor (undefined symbols in preprocessing
+ * expressions are defined to have value zero), but makes it more convenient for
+ * a test program to print out the values.
+ *
+ * If a program mistakenly defines _ANSI_SOURCE and some other macro such as
+ * _POSIX_C_SOURCE, we will assume that it wants the broader compilation
+ * environment (and in fact we will never get here).
+ */
+#if defined(_ANSI_SOURCE)	/* Hide almost everything. */
+#define	__POSIX_VISIBLE		0
+#define	__XSI_VISIBLE		0
+#define	__BSD_VISIBLE		0
+#define	__ISO_C_VISIBLE		1990
+#define	__EXT1_VISIBLE		0
+#elif defined(_C99_SOURCE)	/* Localism to specify strict C99 env. */
+#define	__POSIX_VISIBLE		0
+#define	__XSI_VISIBLE		0
+#define	__BSD_VISIBLE		0
+#define	__ISO_C_VISIBLE		1999
+#define	__EXT1_VISIBLE		0
+#elif defined(_C11_SOURCE)	/* Localism to specify strict C11 env. */
+#define	__POSIX_VISIBLE		0
+#define	__XSI_VISIBLE		0
+#define	__BSD_VISIBLE		0
+#define	__ISO_C_VISIBLE		2011
+#define	__EXT1_VISIBLE		0
+#else				/* Default environment: show everything. */
+#define	__POSIX_VISIBLE		200809
+#define	__XSI_VISIBLE		700
+#define	__BSD_VISIBLE		1
+#define	__ISO_C_VISIBLE		2011
+#define	__EXT1_VISIBLE		1
+#endif
+#endif
+
+/* User override __EXT1_VISIBLE */
+#if defined(__STDC_WANT_LIB_EXT1__)
+#undef	__EXT1_VISIBLE
+#if __STDC_WANT_LIB_EXT1__
+#define	__EXT1_VISIBLE		1
+#else
+#define	__EXT1_VISIBLE		0
+#endif
+#endif /* __STDC_WANT_LIB_EXT1__ */
+
+/*
+ * Old versions of GCC use non-standard ARM arch symbols; acle-compat.h
+ * translates them to __ARM_ARCH and the modern feature symbols defined by ARM.
+ */
+#if defined(__arm__) && !defined(__ARM_ARCH)
+#include <machine/acle-compat.h>
+#endif
+
+/*
+ * Nullability qualifiers: currently only supported by Clang.
+ */
+#if !(defined(__clang__) && __has_feature(nullability))
+#define	_Nonnull
+#define	_Nullable
+#define	_Null_unspecified
+#define	__NULLABILITY_PRAGMA_PUSH
+#define	__NULLABILITY_PRAGMA_POP
+#else
+#define	__NULLABILITY_PRAGMA_PUSH _Pragma("clang diagnostic push")	\
+	_Pragma("clang diagnostic ignored \"-Wnullability-completeness\"")
+#define	__NULLABILITY_PRAGMA_POP _Pragma("clang diagnostic pop")
+#endif
+
+/*
+ * Type Safety Checking
+ *
+ * Clang provides additional attributes to enable checking type safety
+ * properties that cannot be enforced by the C type system. 
+ */
+
+#if __has_attribute(__argument_with_type_tag__) && \
+    __has_attribute(__type_tag_for_datatype__)
+#define	__arg_type_tag(arg_kind, arg_idx, type_tag_idx) \
+	    __attribute__((__argument_with_type_tag__(arg_kind, arg_idx, type_tag_idx)))
+#define	__datatype_type_tag(kind, type) \
+	    __attribute__((__type_tag_for_datatype__(kind, type)))
+#else
+#define	__arg_type_tag(arg_kind, arg_idx, type_tag_idx)
+#define	__datatype_type_tag(kind, type)
+#endif
+
+/*
+ * Lock annotations.
+ *
+ * Clang provides support for doing basic thread-safety tests at
+ * compile-time, by marking which locks will/should be held when
+ * entering/leaving a functions.
+ *
+ * Furthermore, it is also possible to annotate variables and structure
+ * members to enforce that they are only accessed when certain locks are
+ * held.
+ */
+
+#if __has_extension(c_thread_safety_attributes)
+#define	__lock_annotate(x)	__attribute__((x))
+#else
+#define	__lock_annotate(x)
+#endif
+
+/* Structure implements a lock. */
+#define	__lockable		__lock_annotate(lockable)
+
+/* Function acquires an exclusive or shared lock. */
+#define	__locks_exclusive(...) \
+	__lock_annotate(exclusive_lock_function(__VA_ARGS__))
+#define	__locks_shared(...) \
+	__lock_annotate(shared_lock_function(__VA_ARGS__))
+
+/* Function attempts to acquire an exclusive or shared lock. */
+#define	__trylocks_exclusive(...) \
+	__lock_annotate(exclusive_trylock_function(__VA_ARGS__))
+#define	__trylocks_shared(...) \
+	__lock_annotate(shared_trylock_function(__VA_ARGS__))
+
+/* Function releases a lock. */
+#define	__unlocks(...)		__lock_annotate(unlock_function(__VA_ARGS__))
+
+/* Function asserts that an exclusive or shared lock is held. */
+#define	__asserts_exclusive(...) \
+	__lock_annotate(assert_exclusive_lock(__VA_ARGS__))
+#define	__asserts_shared(...) \
+	__lock_annotate(assert_shared_lock(__VA_ARGS__))
+
+/* Function requires that an exclusive or shared lock is or is not held. */
+#define	__requires_exclusive(...) \
+	__lock_annotate(exclusive_locks_required(__VA_ARGS__))
+#define	__requires_shared(...) \
+	__lock_annotate(shared_locks_required(__VA_ARGS__))
+#define	__requires_unlocked(...) \
+	__lock_annotate(locks_excluded(__VA_ARGS__))
+
+/* Function should not be analyzed. */
+#define	__no_lock_analysis	__lock_annotate(no_thread_safety_analysis)
+
+/*
+ * Function or variable should not be sanitized, e.g., by AddressSanitizer.
+ * GCC has the nosanitize attribute, but as a function attribute only, and
+ * warns on use as a variable attribute.
+ */
+#if __has_attribute(no_sanitize) && defined(__clang__)
+#ifdef _KERNEL
+#define __nosanitizeaddress	__attribute__((no_sanitize("kernel-address")))
+#define __nosanitizememory	__attribute__((no_sanitize("kernel-memory")))
+#else
+#define __nosanitizeaddress	__attribute__((no_sanitize("address")))
+#define __nosanitizememory	__attribute__((no_sanitize("memory")))
+#endif
+#define __nosanitizethread	__attribute__((no_sanitize("thread")))
+#else
+#define __nosanitizeaddress
+#define __nosanitizememory
+#define __nosanitizethread
+#endif
+
+/* Guard variables and structure members by lock. */
+#define	__guarded_by(x)		__lock_annotate(guarded_by(x))
+#define	__pt_guarded_by(x)	__lock_annotate(pt_guarded_by(x))
+
+/* Alignment builtins for better type checking and improved code generation. */
+/* Provide fallback versions for other compilers (GCC/Clang < 10): */
+#if !__has_builtin(__builtin_is_aligned)
+#define __builtin_is_aligned(x, align)	\
+	(((__uintptr_t)x & ((align) - 1)) == 0)
+#endif
+#if !__has_builtin(__builtin_align_up)
+#define __builtin_align_up(x, align)	\
+	((__typeof__(x))(((__uintptr_t)(x)+((align)-1))&(~((align)-1))))
+#endif
+#if !__has_builtin(__builtin_align_down)
+#define __builtin_align_down(x, align)	\
+	((__typeof__(x))((x)&(~((align)-1))))
+#endif
+
+#define __align_up(x, y) __builtin_align_up(x, y)
+#define __align_down(x, y) __builtin_align_down(x, y)
+#define __is_aligned(x, y) __builtin_is_aligned(x, y)
+
+#endif /* !_SYS_CDEFS_H_ */