build: remove Windows compatibility layer

For a couple of releases now we have officially withdrawn support for
building TF-A on Windows using the native environment, relying instead
on POSIX emulation layers like MSYS2, Mingw64, Cygwin or WSL.

This change removes the remainder of the OS compatibility layer
entirely, and migrates the build system over to explicitly relying on a
POSIX environment.

Change-Id: I8fb60d998162422e958009afd17eab826e3bc39b
Signed-off-by: Chris Kay <chris.kay@arm.com>
diff --git a/tools/nxp/create_pbl/pbl_ch2.mk b/tools/nxp/create_pbl/pbl_ch2.mk
index bf05a12..47ff892 100644
--- a/tools/nxp/create_pbl/pbl_ch2.mk
+++ b/tools/nxp/create_pbl/pbl_ch2.mk
@@ -1,12 +1,13 @@
 #
 # Copyright 2020 NXP
+# Copyright (c) 2025, Arm Limited and Contributors. All rights reserved.
 #
 # SPDX-License-Identifier: BSD-3-Clause
 #
 #
 
-CREATE_PBL	?=	${CREATE_PBL_TOOL_PATH}/create_pbl${BIN_EXT}
-BYTE_SWAP	?=	${CREATE_PBL_TOOL_PATH}/byte_swap${BIN_EXT}
+CREATE_PBL	?=	${CREATE_PBL_TOOL_PATH}/create_pbl$(.exe)
+BYTE_SWAP	?=	${CREATE_PBL_TOOL_PATH}/byte_swap$(.exe)
 
 HOST_GCC	:= gcc