win32:CONFIG(release, debug|release): LIBS += -L$$PWD/C:/Program Files (x86)/Windows

Kits/8.1/Lib/winv6.3/um/x64/ -lGlU32
else:win32:CONFIG(debug, debug|release): LIBS += -L$$PWD/C:/Program Files (x86)/Windows Kits/8.1/Lib/winv6.3/um/x64/ -lGlU32d

INCLUDEPATH += $$PWD/C:/Program Files (x86)/Windows Kits/8.1/Include/um/gl
DEPENDPATH += $$PWD/C:/Program Files (x86)/Windows Kits/8.1/Include/um/gl

LIBS += glu32

LIBS += Glu32d

-L"$$PWD/C:/Program Files (x86)/Windows"

-L$$quote($$PWD/C:/Program Files (x86)/Windows)

win32: ...
else: win32: ...

QMAKE_LIBDIR += "glu32_location"