LTCG needs to be disabled for WebKit on MSVC2013

Building QtWebKit on Windows 8 64-bit with MSVC 2013 x86 fails due to this error:

lib /NOLOGO /OUT:release\WebCore.lib @C:\Users\SEBAST~1\AppData\Local\Temp\nmB1F8.tmp
moc_QtMIMETypeSniffer.obj : MSIL .netmodule or module compiled with /GL found; restarting link with /LTCG; add /LTCG to the link command line to improve linker performance
LINK : fatal error LNK1248: image size (800001C8) exceeds maximum allowable size (80000000)

This is with LTCG enabled. I found issue QTBUG-20556, which relates to this. The actual project file (qtwebkit/Source/WebCore/WebCore.pri) reads:

win32-msvc2005|win32-msvc2008|win32-msvc2010|win32-msvc2012|wince*:{

this needs to be extended for msvc2013 I guess.