Disable implicit-function-declaration error for newlib

GCC14 will treat implicit-function-declaration as an error by default.
See https://gcc.gnu.org/gcc-14/porting_to.html for details.

Some libc function like __trap34 are defined in assembly and break this GCC diagnostic.

Signed-off-by: Nik Konyuchenko <spaun2002mobile@gmail.com>

scripts/build/libc/newlib.sh

@@ -89,6 +89,9 @@ ENABLE_TARGET_OPTSPACE:target-optspace
     [ "${CT_LIBC_NEWLIB_LTO}" = "y" ] && \
         CT_LIBC_NEWLIB_TARGET_CFLAGS="${CT_LIBC_NEWLIB_TARGET_CFLAGS} -flto"
 
+    [ "${CT_GCC_14_or_later}" = "y" ] && \
+        CT_LIBC_NEWLIB_TARGET_CFLAGS="${CT_LIBC_NEWLIB_TARGET_CFLAGS} -Wno-error=implicit-function-declaration -Wno-implicit-int"
+
     cflags_for_target="${CT_ALL_TARGET_CFLAGS} ${CT_LIBC_NEWLIB_TARGET_CFLAGS}"
 
     # Note: newlib handles the build/host/target a little bit differently