pajlada { BOOST_DIRECTORY = C:\dev\projects\boost_1_66_0\ } win32 { isEmpty(BOOST_DIRECTORY) { message(Using default boost directory C:\\local\\boost\\) BOOST_DIRECTORY = C:\local\boost\ } INCLUDEPATH += $$BOOST_DIRECTORY isEmpty(BOOST_LIB_SUFFIX) { message(Using default boost lib directory suffix lib) BOOST_LIB_SUFFIX = lib } LIBS += -L$$BOOST_DIRECTORY\\$$BOOST_LIB_SUFFIX } else { LIBS += -lboost_system }