compiler: do not allow expansion-to-defined

'-Wexpansion-to-defined'
     Warn whenever 'defined' is encountered in the expansion of a macro
     (including the case where the macro is expanded by an '#if'
     directive).  Such usage is not portable.  This warning is also
     enabled by '-Wpedantic' and '-Wextra'.

This is enabled by default in llvm but not in gcc. Given that it is 'not
portable', lets disallow this in gcc and keep both compilers in sync.

Signed-off-by: Anas Nashif <anas.nashif@intel.com>

cmake/compiler/gcc/compiler_flags.cmake

@@ -39,6 +39,9 @@ check_set_compiler_property(APPEND PROPERTY warning_base -Wno-pointer-sign)
 # Prohibit void pointer arithmetic. Illegal in C99
 check_set_compiler_property(APPEND PROPERTY warning_base -Wpointer-arith)
 
+# not portable
+check_set_compiler_property(APPEND PROPERTY warning_base -Wexpansion-to-defined)
+
 if(CMAKE_CXX_COMPILER_VERSION VERSION_GREATER "9.1.0")
   set_compiler_property(APPEND PROPERTY warning_base
                         # FIXME: Remove once #16587 is fixed