- 
    Bug 
- 
    Resolution: Invalid
- 
    P1: Critical 
- 
    5.6.0 RC
- 
    None
- 
    MSVC2013
In qtwebkit/tools/qmake/mkspecs/features/functions.prf the following code is present:
LIBS += /OPT:REF -l$$target
When building on Windows, the "/OPT:REF" will be converted to "\OPT:REF" (probably by the path separator conversion) and the linker will understand this as a file name rather than an option.
The error message is:
LINK : fatal error LNK1104: cannot open file '\OPT:REF.obj'.