CMakeLists.txt: parse zephyr_stdint.h after compiler specific flags

The zephyr_stdint.h file enforces Zephyr specific policies on the
compilation environment. Let's give compilers a chance to provide
definitions of their own via TOOLCHAIN_C_FLAGS prior the inclusion
of zephyr_stdint.h.

Signed-off-by: Nicolas Pitre <npitre@baylibre.com>

CMakeLists.txt

@@ -220,9 +220,6 @@ toolchain_cc_nostdinc()
 # @Intent: Set compiler specific macro inclusion of AUTOCONF_H
 toolchain_cc_imacros(${AUTOCONF_H})
 
-# @Intent: Enforce standard integer type correspondance to match Zephyr usage.
-toolchain_cc_imacros(${ZEPHYR_BASE}/include/toolchain/zephyr_stdint.h)
-
 # @Intent: Set compiler specific flag for bare metal freestanding option
 toolchain_cc_freestanding()
 
@@ -240,6 +237,10 @@ zephyr_compile_options(
   $<$<COMPILE_LANGUAGE:ASM>:${ASM_BASE_FLAG}>
 )
 
+# @Intent: Enforce standard integer type correspondance to match Zephyr usage.
+# (must be after compiler specific flags)
+toolchain_cc_imacros(${ZEPHYR_BASE}/include/toolchain/zephyr_stdint.h)
+
 # Common toolchain-agnostic assembly flags
 zephyr_compile_options(
   $<$<COMPILE_LANGUAGE:ASM>:-D_ASMLANGUAGE>