INCLUDEPATH *= $$PWD HEADERS += $$PWD/qpnghandler_p.h SOURCES += $$PWD/qpnghandler.cpp contains(QT_CONFIG, system-png) { if(unix|win32-g++*): LIBS_PRIVATE += -lpng else:win32: LIBS += libpng.lib } else { include($$PWD/../../3rdparty/libpng.pri) }