Fix bug in GTK+3 logic introduced by previous merge

During merging of conflicting versions of this file, I erroneously
deleted several lines in the GUI reporting section. This is repaired
in this commit.

CMakeLists.txt

@@ -749,7 +749,6 @@ else()
       endif()
     else()
       status("    GTK+ 2.x:" HAVE_GTK      THEN "YES (ver ${ALIASOF_gtk+-2.0_VERSION})"     ELSE NO)
-      status("    GTK+ 3.x:" HAVE_GTK3     THEN "YES (ver ${ALIASOF_gtk+-3.0_VERSION})"     ELSE NO)
       status("    GThread :" HAVE_GTHREAD  THEN "YES (ver ${ALIASOF_gthread-2.0_VERSION})"  ELSE NO)
       status("    GtkGlExt:" HAVE_GTKGLEXT THEN "YES (ver ${ALIASOF_gtkglext-1.0_VERSION})" ELSE NO)
     endif()