meson: Pass native: false to add_languages()

This is needed for cross-compiling without a build machine compiler available. The option was added in 0.54, but we only need this in Cerbero and it doesn't affect older versions so it should be ok. Will only cause a spurious warning.

Moved from !659 (closed) with a different branch name so it doesn't break because of rebasing in other modules.

meson.build

@@ -16,8 +16,8 @@ else
 endif
 gst_version_is_dev = gst_version_minor % 2 == 1 and gst_version_micro < 90
 
-have_cxx = add_languages('cpp', required : false)
-have_objc = add_languages('objc', required : false)
+have_cxx = add_languages('cpp', native: false, required: false)
+have_objc = add_languages('objc', native: false, required: false)
 
 glib_req = '>= 2.44.0'
 orc_req = '>= 0.4.24'