Merging r143896:

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r143896 | chandlerc | 2011-11-06 15:09:05 -0800 (Sun, 06 Nov 2011) | 3 lines

Remove the HasMultilib check. It was essentially useless. The driver now
looks for evidence of a multilib installation, and adds the appropriate
bits to the search paths.
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llvm-svn: 143953