compiler object methods don't warn about unknown kwargs

[ystreet]

As mentioned on the tin.

https://cgit.freedesktop.org/gstreamer/gst-plugins-bad/tree/gst-libs/gst/gl/meson.build?id=980ddfdfb740107ce8d9db3f8679d235af757412#n366

Which results in:

Command line:  ccache cc /tmp/tmp3s718w9b/testfile.c -O0 -pipe -D_FILE_OFFSET_BITS=64 -c -o /tmp/tmp3s718w9b/output.obj 

Code:
 void f (void) {}
Compiler stdout:
 
Compiler stderr:

We either need to add support for the prefix kwarg or error out on its use in cc.compiles().

GStreamer bug: https://bugzilla.gnome.org/show_bug.cgi?id=787964

[nirbheek]

Hmm, looks like we don't use the @permittedKwargs decorator for compiler methods.

[tp-m]

Is there a consensus on whether cc.compiles() should support prefix: or not?

[nirbheek]

No, but I guess we should add it just for consistency? It would make the reference manual simpler too.

[tp-m]

We should decide if we want a prefix: kwarg for cc.compiles() or not.

If not, we can close this bug, because we do get warnings now. If yes, we should retitle.