Is there a way to add build flags to a project in QtCreator? For example release, debug, libs, or includepath?

Sure, I can exit QtCreate and manually edit my *.pro file to add (for example)

INCLUDEPATH += C:\qwt-5.2.0\src
LIBS += C:\qwt-5.2.0\lib\qwtd5.lib

and then nmake from the command line. (which works...)

But is there a way to make these additions as default from within QtCreator?