Merging r234977:

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r234977 | lhames | 2015-04-15 00:46:01 -0400 (Wed, 15 Apr 2015) | 5 lines

[RuntimeDyld] Add casts to make delta computation 64-bit.

Hopefully this will fix the i686/msvc build failure described at:
http://bb.pgr.jp/builders/ninja-clang-i686-msc18-R/builds/803

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llvm-svn: 236784