find bin, lib and include locations

[jpn]

jpnurmi@jaber:~$ qmake -query QT_INSTALL_LIBS
/usr/local/Trolltech/Qt-4.5.3/lib
jpnurmi@jaber:~$ qmake -query QT_INSTALL_HEADERS
/usr/local/Trolltech/Qt-4.5.3/include

jpnurmi@jaber:~$ qmake -query QT_INSTALL_LIBS
/usr/local/Trolltech/Qt-4.5.3/lib
jpnurmi@jaber:~$ qmake -query QT_INSTALL_HEADERS
/usr/local/Trolltech/Qt-4.5.3/include

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You can refer the variables within .pro files as $$[QT_INSTALL_LIBS] and so on. See [wiki]undocumented qmake[/wiki] for more info.