Have a SomeLib.pro file that contains:
CONFIG += debug TEMPLATE = lib TARGET = SomeLib ..
Then in a dependent SomeApp.pro:
.. debug:LIBS += -lSomeLib_debug ..
How can I force SomeApp to build if I touched SomeLib in qmake?
It's ugly because you need to give the exact library file name, but this should work:
TARGETDEPS += libfoo.a
QT Creator will do the work if you click "Add library..." in the context menu of the project that should include the library.
These variables are configured automatically for you: