--- pkgsrc-cvs/devel/cmake/Makefile    2017-07-07 17:05:48.317663687 +0200
+++ pkgsrc/devel/cmake/Makefile    2017-07-10 13:54:53.437288060 +0200
@@ -55,6 +55,15 @@
 SUBST_FILES.flags=     Modules/Compiler/*.cmake
 SUBST_SED.flags=       -e 's,-O.,,'
 
+# Breaks when it does not like our Gtk+2/glibmm setup.
+# As this is only for tests, rather avoid use of (system)
+# Gtk+2 altogether.
+SUBST_CLASSES+=                gtktest
+SUBST_FILES.gtktest+=  Tests/CMakeLists.txt
+SUBST_STAGE.gtktest=   pre-configure
+SUBST_SED.gtktest=     -e '/add_subdirectory(FindGTK2)/s/^/\#/'
+SUBST_MESSAGE.gtktest= Avoiding unnecessary possible Gtk+2/gtkmm test breakage.
+
 pre-configure:
        ${RM} -f ${WRKSRC}/Modules/*.orig ${WRKSRC}/Modules/Platform/*.orig
        ${LN} -f ${WRKSRC}/Modules/Platform/OpenBSD.cmake ${WRKSRC}/Modules/Platform/MirBSD.cmake