qmldump does not build with clang

Error running '/usr/bin/make' in /Users/fabien/Qt/build-staging-2/qtc-qmldump/: The process returned exit code 2: 
clang++ -c -pipe -Xarch_x86_64 -mmacosx-version-min=10.5 -g -gdwarf-2 -arch x86_64 -Wall -W -D_LARGEFILE64_SOURCE -D_LARGEFILE_SOURCE -DQT_DECLARATIVE_LIB -DQT_GUI_LIB -DQT_CORE_LIB -DQT_HAVE_MMX -DQT_HAVE_SSE2 -DQT_HAVE_SSE3 -DQT_HAVE_SSSE3 -DQT_HAVE_SSE4_1 -DQT_HAVE_SSE4_2 -DQT_SHARED -I/Users/fabien/Qt/oslo-staging-2/mkspecs/unsupported/macx-clang -I. -I../lib/QtCore.framework/Versions/4/Headers -I../include/QtCore -I../lib/QtGui.framework/Versions/4/Headers -I../include/QtGui -I../lib/QtDeclarative.framework/Versions/4/Headers -I../include/QtDeclarative -I../include -I.moc/debug-shared -F/Users/fabien/Qt/build-staging-2/lib -o .obj/debug-shared/main.o main.cpp 
clang: error: invalid Xarch argument: '-Xarch_x86_64 -mmacosx-version-min=10.5' 
make: *** [.obj/debug-shared/main.o] Error 1