Fix compile for OS(WIN) != PLATFORM(WIN)
Created attachment 195193 [details] Patch
146932 broke the build for all windows ports that aren't the apple-win port. PLATFORM(WIN) means the apple-win port, not windows the operating system (just as PLATFORM(MAC) means the apple-mac port, not Mac OS X).
Committed r146948: <http://trac.webkit.org/changeset/146948>