GCC: Fix compiling on Yosemite

As far as I can tell, the issue with `_Unwind_GetIPInfo` was fixed upstream before 4.9.1, so it is no longer required. Instead, I have added a patch which both fixes `version_as_macro` (it previously assumed there was only one digit for the minor OS version) and issues in `libsanitizer` relating to `__DARWIN_64_BIT_INO_T`. This patch is a modified version of https://gcc.gnu.org/bugzilla/attachment.cgi?id=32949.