#7 Fix OS X 10.8.5/LLVM-GCC compile

[Joseph Osborn]

Hello again! I noticed that the latest XSB won't compile on OS X 10.8.5/LLVM-GCC 5.0, and I tried earlier revisions but no luck there either. So I mucked around with configure.in (to remove -faltivec for non-PPC Darwin) and, more scarily, I changed a bunch of inline functions that weren't linking properly to be static inline (in C files) or extern inline (in header files), and I was able to get XSB building again.

Speed doesn't seem to have been impaired by the change, so I don't think I broke anything that had been inlining before, but I haven't written much C for a while.

I have not tested this change on other platforms (older LLVM-GCC, older Mac OS, PPC Mac OS, or non-Mac OS systems).