meson: Use get_supported_arguments()

Instead of iterating over the list of compiler flags, we should use the
get_supported_arguments() method of the compiler object, which does it
for us — and maybe, in the future, will be optimised to do the checks in
parallel.

meson.build

@@ -159,12 +159,7 @@ else
   test_cflags = []
 endif
 
-common_cflags = []
+common_cflags = cc.get_supported_arguments(test_cflags)
-foreach cflag: test_cflags
-  if cc.has_argument(cflag)
-    common_cflags += cflag
-  endif
-endforeach
 
 libtype = get_option('default_library')