Attempt to detect the correct processor type under Snow Leopard's gdb.

Unfortunately, gdb under Snow Leopard doesn't give a useful doublet.  So
let's go the extra step and grab the osabi and use it to determine what
processor we're using and the size.
Merge pull request #3 from jszakmeister/fix-detection-on-snow-leopard

Attempt to detect the correct processor type under Snow Leopard's gdb.