Support statically linking the MSVC/mingw runtime libraries without
manually tweaking mkspecs. This is helpful for projects like the
installer framework.
MSVC does not support mixing MT[d]/MD[d] flags in different
compilation units. The static_runtime option is therefore added
to both QT_CONFIG and CONFIG.
Change-Id: Ifd6dc9c362090457de8e2c62477d0445f9479722
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@theqtcompany.com>
