[Cairo] slim committed; used by pixregion

[Billy Biggs]

Richard Henderson (rth at twiddle.net):

> I've now committed the contents of the slim module, and
> have updated libpixregion to use it.

  You use the visibility attribute for gcc >= 3.2, however
here with gcc 3.2.3 the attribute gives a warning.

#if (__GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ >= 2)) && defined(__ELF__)
#define __internal_linkage      __attribute__ ((__visibility__ ("hidden")))

  As well, the docs on the gcc site say that the attribute
name is 'visibility' not '__visibility__'  (neither works with
3.2.3 fwiw).

  Thoughts?
  -Billy