[CMake] Trouble with non standard Qt installation.

[tibur]

Hello.

Our team uses the same Windows (VS) Qt build, but all the developers 
don't store it at the same place on their hard drive. So qmake.exe 
doesn't contain the good include, library, ... directories.

On the FindQt4.cmake script of version 2.8.2 (line 770), the 
find_library call was using QT_LIBRARY_DIR variable to find the possible 
location of QtCore.lib, ...

But on version 2.8.3, this module now queries qmake.exe to retrieve the 
library and includes path. This stuck us to the 2.8.2 version of CMake, 
since qmake doesn't return the good directories.

How can we fix that?

Thanks,
Thibaut