hidden visibility on mac (Re: [PUSHED][3-5] Re: [REVIEW 3-5] fdo#37044 crash on mac with transliteration)

[Tor Lillqvist]

> Yes, seems to work, so pushed.

That was a bit premature, I hadn't noticed that in fact the
-fvisible=hidden stuff didn't get passed to the compiler after all
thanks to the order of assignments to the gb_C*FLAGS variables in the
gbuild macosx,mk file. I fixed that, and now then I get linking errors
in lingucomponent. Please, don't panic and start reverting my changes,
I am investigating.

--tml