[PyQt] Unquoted Python LIBS path while building PyQt5 5.14.1 in Windows

[Kyle Altendorf]

I'm using sip-build as part of the pyqt5-tools build process (trying to 
catch it up...) and while it's running ok in GitHub Actions I am getting 
an error locally in Windows.  Cherry picking the part of interest 
(hopefully correctly):

     LINK : fatal error LNK1181: cannot open input file 
'Files\Python38\libs.obj'

That looks like an unquoted use of "Program Files".  I searched around 
in the build directory and found the following in three .pro files (I'm 
not building most of the modules).

     INCLUDEPATH += $$quote(C:/Program Files/Python38/include)
     win32 {
         LIBS += -LC:\Program Files\Python38\libs
     }

This is part of SIP generation?  I'm guessing the LIBS should get 
$$quote()'ed as well?  Doing so seemed to fix the above error anyways, 
now time for me to dig into the rest.

Thanks.

Cheers,
-kyle