[CMake] CHECK_C_SOURCE_COMPILES for objective c?

[Doug]

Small query:

Checking for the presence of cocoa like this fails:

    check_c_source_compiles("
        #import <Cocoa/Cocoa.h>
        int main (int argc, char** argv) {}" HAVE_VIDEO_COCOA)

Because compiling blah.c with that content fails, where compiling
blah.m with that content passes.

What's the right way of handling this?

~
Doug.