from https://blog.gtk.org/2016/10/11/this-week-in-gtk-19/ " Matthias is working on the build system to ensure that the master branch is parallel installable with the gtk-3-22 and gtk-2-24 stable branches The old and deprecated AM_PATH_GTK_3_0 m4 macro for autotools-based build systems has been removed from the master branch; projects depending on GTK+ 3.x should already have been ported to just use pkg-config and the PKG_CHECK_MODULES macro instead. " so i removed from Makefile.in the line: PKG_CONFIG_PATH = @PKG_CONFIG_PATH@ and now i becomes a good result ./configure --enable-gtk3 --enable-gladeui --enable-gladeui2 before nothings find with pkgconfig-test for gtk3 and gladeui2 Please checked if this will also affected in gtk2 and other projects on xfce! Thank you for the best DE on this world! onkelho
it's come from broken or corrupted autoreconf on my buildsystem - Please ignore the bug-report! - It's solved, the line is not created anymore by build, since changed my build-tools. Best Regards!
Closing