[Bug objc/117478] -ObjC is not accepted: error: argument to '-O' should be a non-negative integer, 'g', 's', 'z' or 'fast'

[eschwartz93 at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117478

--- Comment #5 from Eli Schwartz <eschwartz93 at gmail dot com> ---
https://github.com/GNOME/gegl/blob/626c202550c4536c2e411821fb34e91d138c1548/meson.build#L246-L254

```
if os_osx
  add_languages('objc')
  osx_ldflags = ['-Wl,-framework,Foundation', '-Wl,-framework,AppKit', '-ObjC']
  add_project_link_arguments(osx_ldflags, language : ['objc', 'c'])
endif

if os_osx
  add_project_arguments('-ObjC', language : 'c')
endif
```

Not a meson bug, but gegl should probably test whether -ObjC is accepted as a
valid flag before unconditionally adding it to their build.