Qmake does not specify a valid qt

After installing Qt SDK for Open Source C++ development on Mac OS by following the respective steps

Note for the binary package: If you have the binary package, simply double-click on the Qt.mpkg and follow the instructions to install Qt.

Yes, that is all I have done to install Qt on MacOsX. Everything was going fine, until I run a sample application, of which compile output resulted in:

No valid Qt version set.
Set one in Preferences
Error while building project qtilk
When executing build step 'QMake'
Canceled build.

Then I tried to change the respective Qt version in Preferences and I hovered over the Path, I realized my mkspec isn't set:

Then I tried querying qmake by qmake -query:

QT_INSTALL_PREFIX:/
QT_INSTALL_DATA:/usr/local/Qt4.6
QT_INSTALL_DOCS:/Developer/Documentation/Qt
QT_INSTALL_HEADERS:/usr/include
QT_INSTALL_LIBS:/Library/Frameworks
QT_INSTALL_BINS:/Developer/Tools/Qt
QT_INSTALL_PLUGINS:/Developer/Applications/Qt/plugins
QT_INSTALL_TRANSLATIONS:/Developer/Applications/Qt/translations
QT_INSTALL_CONFIGURATION:/Library/Preferences/Qt
QT_INSTALL_EXAMPLES:/Developer/Examples/Qt/
QT_INSTALL_DEMOS:/Developer/Examples/Qt/Demos
**QMAKE_MKSPECS:/usr/local/Qt4.6/mkspecs**
QMAKE_VERSION:2.01a
QT_VERSION:4.6.2

QMAKE_MKSPECS seems to be set here??

Will setting my mkspec solve my building problem? I tried setting by typing expor开发者_开发技巧t mkspec=macx-g++. Still, mkspec seems not to be set to anything. I am all ears waiting for your answers. Thanks in advance.

To set the correct spec, use: qmake -spec max-g++