Merging r236299:

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r236299 | ericwf | 2015-04-30 18:49:37 -0700 (Thu, 30 Apr 2015) | 7 lines

Disallow conversions from function pointers to void*.

Function pointers and member function pointers cannot be converted to void*.
libc++abi incorrectly allows this conversion for function pointers.

Review URL: http://reviews.llvm.org/D8811

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llvm-svn: 236868