Merging r228507:

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r228507 | joerg | 2015-02-07 13:24:06 -0800 (Sat, 07 Feb 2015) | 4 lines

Avoid integer overflows around realloc calls resulting in potential
heap. Problem identified by Guido Vranken. Changes differ from original
OpenBSD sources by not depending on non-portable reallocarray.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_36@228511 91177308-0d34-0410-b5e6-96231b3b80d8