Merging r277093:

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r277093 | eugenezelenko | 2016-07-28 17:46:13 -0700 (Thu, 28 Jul 2016) | 4 lines

Add LLVM_ENABLE_LLD option to use LLD as C/C++ linker.

Differential revision: https://reviews.llvm.org/D22896

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llvm-svn: 278428