qmleasing is not properly built as a qt tool

Using the configure line:

../qt-everywhere-opensource-src-5.3.0-beta/configure -sdk macosx10.9 -warnings-are-errors -system-proxies -no-linuxfb -no-directfb -no-dbus -pch -optimized-qmake -v -no-compile-examples -nomake examples -no-glib -opensource -confirm-license -force-debug-info -debug-and-release -prefix `(cd ../qt-everywhere-opensource-src-5.3.0-beta-deploy/; pwd -P)` -icu -no-xcb -I /opt/local/include -L /opt/local/lib

… and also with the following environment variables set:

MACOSX_DEPLOYMENT_TARGET=10.7
CXXFLAGS=-stdlib=libc++

… the build proceeds as normal for a long time, but then the qtdeclarative build fails.

The reason for this is that it is ignoring the MACOSX_DEPLOYMENT_TARGET variable.

Fragment of build output:

{{cd qmleasing/ && ( test -e Makefile || /Users/williamg/Projects/VertusLLP/Development/Vendor/qt-everywhere-opensource-src-5.3.0-beta-build/qtbase/bin/qmake /Users/williamg/Projects/VertusLLP/Development/Vendor/qt-everywhere-opensource-src-5.3.0-beta/qtdeclarative/tools/qmleasing/qmleasing.pro -o Makefile ) && /Applications/Xcode.app/Contents/Developer/usr/bin/make -f Makefile
/Users/williamg/Projects/VertusLLP/Development/Vendor/qt-everywhere-opensource-src-5.3.0-beta-build/qtbase/bin/qmake -o Makefile /Users/williamg/Projects/VertusLLP/Development/Vendor/qt-everywhere-opensource-src-5.3.0-beta/qtdeclarative/tools/qmleasing/qmleasing.pro}}
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang++ -c -stdlib=libc++ -g -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk -mmacosx-version-min=10.6 -fno-exceptions -Wall -W -fPIE -DQT_NO_MTDEV -DQT_NO_LIBUDEV -DQT_NO_EVDEV -DQT_NO_EXCEPTIONS -D_LARGEFILE64_SOURCE -D_LARGEFILE_SOURCE -DQT_QUICK_LIB -DQT_QML_LIB -DQT_WIDGETS_LIB -DQT_NETWORK_LIB -DQT_GUI_LIB -DQT_CORE_LIB -I/Users/williamg/Projects/VertusLLP/Development/Vendor/qt-everywhere-opensource-src-5.3.0-beta/qtbase/mkspecs/macx-clang -I/Users/williamg/Projects/VertusLLP/Development/Vendor/qt-everywhere-opensource-src-5.3.0-beta/qtdeclarative/tools/qmleasing -I/opt/local/include -I../../lib/QtQuick.framework/Versions/5/Headers -I../../lib/QtQml.framework/Versions/5/Headers -I/Users/williamg/Projects/VertusLLP/Development/Vendor/qt-everywhere-opensource-src-5.3.0-beta-build/qtbase/lib/QtWidgets.framework/Versions/5/Headers -I/Users/williamg/Projects/VertusLLP/Development/Vendor/qt-everywhere-opensource-src-5.3.0-beta-build/qtbase/lib/QtNetwork.framework/Versions/5/Headers -I/Users/williamg/Projects/VertusLLP/Development/Vendor/qt-everywhere-opensource-src-5.3.0-beta-build/qtbase/lib/QtGui.framework/Versions/5/Headers -I/Users/williamg/Projects/VertusLLP/Development/Vendor/qt-everywhere-opensource-src-5.3.0-beta-build/qtbase/lib/QtCore.framework/Versions/5/Headers -I.moc -I/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/System/Library/Frameworks/OpenGL.framework/Versions/A/Headers -I/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk/System/Library/Frameworks/AGL.framework/Headers -I.uic -I. -F/Users/williamg/Projects/VertusLLP/Development/Vendor/qt-everywhere-opensource-src-5.3.0-beta-build/qtdeclarative/lib -F/Users/williamg/Projects/VertusLLP/Development/Vendor/qt-everywhere-opensource-src-5.3.0-beta-build/qtbase/lib -o .obj/main.o /Users/williamg/Projects/VertusLLP/Development/Vendor/qt-everywhere-opensource-src-5.3.0-beta/qtdeclarative/tools/qmleasing/main.cpp
clang: error: invalid deployment target for -stdlib=libc++ (requires OS X 10.7 or later)
make[3]: *** [.obj/main.o] Error 1
make[2]: *** [sub-qmleasing-make_first] Error 2
make[1]: *** [sub-tools-make_first] Error 2
make: *** [module-qtdeclarative-make_first] Error 2
forth:qt-everywhere-opensource-src-5.3.0-beta-build williamg$ echo $MACOSX_DEPLOYMENT_TARGET
10.7

A randomly chosen fragment from earlier in the build shows that here it /is/ being honoured:

/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang++ -headerpad_max_install_names -Wl,-syslibroot,/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.9.sdk -stdlib=libc++ -mmacosx-version-min=10.7 -o ../../bin/qmlprofiler .obj/main.o .obj/qmlprofilerapplication.o .obj/commandlistener.o .obj/qqmldebugclient.o .obj/qmlprofilerdata.o .obj/qmlprofilerclient.o .obj/qpacketprotocol.o .obj/moc_qmlprofilerapplication.o .obj/moc_commandlistener.o .obj/moc_qmlprofilerdata.o .obj/moc_qmlprofilerclient.o .obj/moc_qqmldebugclient.o .obj/moc_qpacketprotocol.o -F/Users/williamg/Projects/VertusLLP/Development/Vendor/qt-everywhere-opensource-src-5.3.0-beta-build/qtdeclarative/lib -F/Users/williamg/Projects/VertusLLP/Development/Vendor/qt-everywhere-opensource-src-5.3.0-beta-build/qtbase/lib -L/opt/local/lib -framework QtQml -framework QtNetwork -framework QtCore

… so it looks as if there's something odd in this bit of the qtdeclarative build system which is ignoring the MACOSX_DEPLOYMENT_TARGET=10.7 in the environment, where other bits of the build system are honouring it happily.