I want to use Qt feature FOO but there is no corresponding checkbox in project properties. What can I do?
Qt build system (qmake) has so many features and configuration options, that it's impossible to put them in a nice and simple GUI. NetBeans project properties have GUI controls for most common properties only.
If you need something special, put your qmake code into Qt -> Expert -> Custom Definitions in project properties. Editing *.pro files under nbproject/ directly is not recommended, because those files are overwritten automatically without warning.
See Qmake Variable Reference for description of qmake variables.
Q: How do I enable QtScript module?
A: Add QT += script to Qt -> Expert -> Custom Definitions.
Q: How do I add compiler flag -std=gnu++0x?
A: Add QMAKE_CXXFLAGS += -std=gnu++0x to Qt -> Expert -> Custom Definitions.