I build webkit under mingw/msys ans the isnan() cannot be found there, because it's defined in std:: nasmespace. A similar change had been done in Source/JavaScriptCore/profiler/ProfileGenerator.cpp recently too.
Created attachment 240277 [details] proposed wk patch
Comment on attachment 240277 [details] proposed wk patch Clearing flags on attachment: 240277 Committed r175089: <http://trac.webkit.org/changeset/175089>
All reviewed patches have been landed. Closing bug.