1 INCLUDEPATH *= $$PWD

     2 HEADERS += $$PWD/qpnghandler_p.h

     3 SOURCES += $$PWD/qpnghandler.cpp

     4 contains(QT_CONFIG, system-png) {

     5     if(unix|win32-g++*): LIBS_PRIVATE  += -lpng

     6     else:win32:          LIBS += libpng.lib

     7 

     8 } else {

     9     include($$PWD/../../3rdparty/libpng.pri)

    10 }