meson: use add_project_arguments instead of global

The `add_global*_arguments` family of functions affect subprojects, and
are therefore generally discouraged from being used.

Fixes: a42c2293ab ("wsi: Metal support")
Reviewed-by: Erik Faye-Lund <erik.faye-lund@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/31267>

meson.build

@@ -19,7 +19,7 @@ project(
 
 if host_machine.system() == 'darwin'
   add_languages('objc', native : false)
-  add_global_arguments('-fobjc-arc', language : 'objc')
+  add_project_arguments('-fobjc-arc', language : 'objc')
 endif
 
 cc = meson.get_compiler('c')