Can't parse png.h from libpng 1.2

[raydiak]

Things which don't work seem to include extension and declarations like "typedef unsigned (*in_func) (void *, unsigned char * *);". Also seeing "unknown condition in typedef!" 6 times, though the error doesn't point to exactly what causes it.

[andydude]

I added the __extension__ keyword to the Grammar and the Actions, and so now it will at least parse png.h, but the conversion to C::AST is failing for some other reason. I will look at this again when I have time.