BUILD: syscalls: remove improper inline statement in front of syscalls

Trying to build with an old gcc and glibc revealed that we must not
state "inline" in our _syscall* definitions since it's already present
in the declaration making use of the _syscall* macros.
diff --git a/include/common/accept4.h b/include/common/accept4.h
index 1130ecc..8981b92 100644
--- a/include/common/accept4.h
+++ b/include/common/accept4.h
@@ -58,7 +58,7 @@
 	return socketcall(SYS_ACCEPT4, args);
 }
 #else
-static _syscall4(int, accept4, int, sockfd, struct sockaddr *, addr, socklen_t *, addrlen, int, flags);
+static inline _syscall4(int, accept4, int, sockfd, struct sockaddr *, addr, socklen_t *, addrlen, int, flags);
 #endif /* VSYSCALL etc... */
 #endif /* USE_MY_ACCEPT4 */
 #endif /* __linux__ && USE_ACCEPT4 */
diff --git a/include/common/splice.h b/include/common/splice.h
index a776b9b..ea29b16 100644
--- a/include/common/splice.h
+++ b/include/common/splice.h
@@ -62,7 +62,7 @@
 #define __NR_splice             313
 #endif /* __NR_splice */
 
-static _syscall6(int, splice, int, fdin, loff_t *, off_in, int, fdout, loff_t *, off_out, size_t, len, unsigned long, flags);
+static inline _syscall6(int, splice, int, fdin, loff_t *, off_in, int, fdout, loff_t *, off_out, size_t, len, unsigned long, flags);
 #endif /* VSYSCALL */
 
 #else
diff --git a/include/common/syscall.h b/include/common/syscall.h
index 0b1ccd6..7c9a456 100644
--- a/include/common/syscall.h
+++ b/include/common/syscall.h
@@ -37,42 +37,42 @@
  */
 #ifndef _syscall1
 #define _syscall1(tr, nr, t1, n1)              \
-	inline tr nr(t1 n1) {		       \
+	tr nr(t1 n1) {	                       \
 		return syscall(__NR_##nr, n1); \
 	}
 #endif
 
 #ifndef _syscall2
 #define _syscall2(tr, nr, t1, n1, t2, n2)          \
-	inline tr nr(t1 n1, t2 n2) {               \
+	tr nr(t1 n1, t2 n2) {                      \
 		return syscall(__NR_##nr, n1, n2); \
 	}
 #endif
 
 #ifndef _syscall3
 #define _syscall3(tr, nr, t1, n1, t2, n2, t3, n3)      \
-	inline tr nr(t1 n1, t2 n2, t3 n3) {            \
+	tr nr(t1 n1, t2 n2, t3 n3) {                   \
 		return syscall(__NR_##nr, n1, n2, n3); \
 	}
 #endif
 
 #ifndef _syscall4
 #define _syscall4(tr, nr, t1, n1, t2, n2, t3, n3, t4, n4)  \
-	inline tr nr(t1 n1, t2 n2, t3 n3, t4 n4) {         \
+	tr nr(t1 n1, t2 n2, t3 n3, t4 n4) {                \
 		return syscall(__NR_##nr, n1, n2, n3, n4); \
 	}
 #endif
 
 #ifndef _syscall5
 #define _syscall5(tr, nr, t1, n1, t2, n2, t3, n3, t4, n4, t5, n5) \
-	inline tr nr(t1 n1, t2 n2, t3 n3, t4 n4, t5 n5) {         \
+	tr nr(t1 n1, t2 n2, t3 n3, t4 n4, t5 n5) {                \
 		return syscall(__NR_##nr, n1, n2, n3, n4, n5);    \
 	}
 #endif
 
 #ifndef _syscall6
 #define _syscall6(tr, nr, t1, n1, t2, n2, t3, n3, t4, n4, t5, n5, t6, n6) \
-	inline tr nr(t1 n1, t2 n2, t3 n3, t4 n4, t5 n5, t6 n6) {          \
+	tr nr(t1 n1, t2 n2, t3 n3, t4 n4, t5 n5, t6 n6) {                 \
 		return syscall(__NR_##nr, n1, n2, n3, n4, n5, n6);        \
 	}
 #endif