qmake to build both 32-bit and 64-bit

[lni]

Because now, even if you change QMAKESPEC, qmake will use libraries from $QTDIR and these are either 32-bit or 64-bit, but not both at the same time.

I think I can do like

for 32:
CONFIG -= qt
LIBS += the-32-bit-libaries

for 64:
CONFIG -= qt
LIBS += the-64-bit-libaries

The "CONFIG -= qt" is to tell qmake not to go with the qt configuration's makespec.

No? qmake should not tie to the qt configuration. It is a tool on top of gmake, but if it ties to the qt configuration, then it become useless tool when you have to build both 32-bit and 64-bit, which is the case in most companies...