Merging r229529:

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r229529 | rnk | 2015-02-17 12:02:34 -0800 (Tue, 17 Feb 2015) | 8 lines

Expose LLVM_VERSION_PATCH in llvm-config.h

There was no reason to keep this private in config.h, and users
requested that it be available in PR22615.

Also fix a bug where patch versions of '0' would cause the macro to
remain undefined. The "#cmakedefine" command only creates a macro if the
named variable would be considered true in the context of an if().
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_36@229567 91177308-0d34-0410-b5e6-96231b3b80d8