[ Copied from https://llvm.org/bugs/show_bug.cgi?id=26404 ]
clang support on Haiku is lagging a bit, and missing on x86_64.
This patch updates support for x86 and add support for x86_64. It should apply directly to trunk and it's harmless in the sense that it only affects Haiku.
Please consider reviewing.
This doesn't exist here any more.