contains(QT_CONFIG, system-png) {
    unix|mingw {
        !contains(QT_CONFIG, no-pkg-config) {
            CONFIG += link_pkgconfig
            PKGCONFIG_PRIVATE += libpng
        } else {
            LIBS_PRIVATE += -lpng
        }
    } else {
        LIBS += libpng.lib
    }
} else: contains(QT_CONFIG, png) {
    INCLUDEPATH += $$PWD/libpng
    LIBS_PRIVATE += -L$$QT_BUILD_TREE/lib -lqtpng$$qtPlatformTargetSuffix()
}