Problem with Qt5 installation in Mac Snow Leopard

[mossqt]

I have downloaded the source code and tried to build Qt from scratch. Both the versions failed to installed (5.0.2 & 4.8.4). I have a mac snowleopard (v 10.6.8, 64 bit). Recently I have updated gcc using macports and redirected gcc to gcc4.7 (using: sudo port select --set gcc mp-gcc47). Not sure if this broke something in Xcode. I have Xcode version 3.2.2. Can anyone help me and point out what the problem is. Here's is the error message for 5.0.2:

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Creating qmake...
g++ -c -o project.o -pipe -mmacosx-version-min=10.6 -DQMAKE_OPENSOURCE_EDITION -g -gdwarf-2 -fconstant-cfstrings -g -I/Users/promita/Downloads/qt-everywhere-opensource-src-5.0.2/qtbase/qmake -I/Users/promita/Downloads/qt-everywhere-opensource-src-5.0.2/qtbase/qmake/library -I/Users/promita/Downloads/qt-everywhere-opensource-src-5.0.2/qtbase/qmake/generators -I/Users/promita/Downloads/qt-everywhere-opensource-src-5.0.2/qtbase/qmake/generators/unix -I/Users/promita/Downloads/qt-everywhere-opensource-src-5.0.2/qtbase/qmake/generators/win32 -I/Users/promita/Downloads/qt-everywhere-opensource-src-5.0.2/qtbase/qmake/generators/mac -I/Users/promita/Downloads/qt-everywhere-opensource-src-5.0.2/qtbase/qmake/generators/integrity -I/Users/promita/Downloads/qt-everywhere-opensource-src-5.0.2/qtbase/include -I/Users/promita/Downloads/qt-everywhere-opensource-src-5.0.2/qtbase/include/QtCore -I/Users/promita/Downloads/qt-everywhere-opensource-src-5.0.2/qtbase/include/QtCore/5.0.2 -I/Users/promita/Downloads/qt-everywhere-opensource-src-5.0.2/qtbase/include/QtCore/5.0.2/QtCore -I/Users/promita/Downloads/qt-everywhere-opensource-src-5.0.2/qtbase/src/corelib/global -DHAVE_QCONFIG_CPP -I/Users/promita/Downloads/qt-everywhere-opensource-src-5.0.2/qtbase/mkspecs/macx-g++ -I/Users/promita/Downloads/qt-everywhere-opensource-src-5.0.2/qtbase/tools/shared -DQT_BUILD_QMAKE -DQT_BOOTSTRAPPED -DPROEVALUATOR_FULL -DPROEVALUATOR_DEBUG -DQT_NO_TEXTCODEC -DQT_NO_UNICODETABLES -DQT_NO_COMPONENT -DQT_NO_COMPRESS -DQT_NO_THREAD -DQT_NO_QOBJECT -DQT_NO_GEOM_VARIANT -DQT_NO_DATASTREAM /Users/promita/Downloads/qt-everywhere-opensource-src-5.0.2/qtbase/qmake/project.cpp
g++: error: unrecognized command line option '-fconstant-cfstrings'
gmake: *** [project.o] Error 1
*** qtbase/configure exited with non-zero status.
58-b0-35-82-75-32:qt-everywhere-opensource-src-5.0

[mossqt]

Update: It also does not compile with gcc 4.2 (Xcode version). I will appreciate any lead in this. Thanks.