r224012 - Emit warning if define or undef reserved identifier or keyword.

[Joerg Sonnenberger]

On Thu, Dec 11, 2014 at 12:18:09PM -0000, Serge Pavlov wrote:
> Author: sepavloff
> Date: Thu Dec 11 06:18:08 2014
> New Revision: 224012
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=224012&view=rev
> Log:
> Emit warning if define or undef reserved identifier or keyword.
> 
> Recommit of r223114, reverted in r223120.

FYI, I've disabled the warning in r224433 for now, until the discussed
changes are applied.

Joerg