Fix Mac after r169880.

This revision added a C++ comment to Platform.h, which breaks sandbox profile
preprocessing.

Also, I do not believe that this comment was entirely accurate - we've always used
this technique with GCC, so there has to be more to it. So, I just removed the comment.

* wtf/Platform.h:



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@169900 268f45cc-cd09-0410-ab3c-d52691b4dbfc