[CMake] another name for Qt4 qmake

[Bill Hoffman]

Matthieu Brucher wrote:
> First qmake-qt4 or qmake4, qmake is also used for Qt3, so the 
> can-confuse qmake should not be searched for first.

This should be fixed in the current cmake release.  It should do this:

1. look for qmake
  -  if the qmake it finds is for qt3 then look for qmake-qt4
2. look for qmake-qt4

I have tested this on a machine with qmake and qmake-qt4 in the PATH and it
correctly finds qmake-qt4.

-Bill