Remove HAVE_CONFIG_H defs and uses
Since GLib files are only meant to be built as part of GLib, config.h always exists, so the checks are more or less pointless. https://bugzilla.gnome.org/show_bug.cgi?id=793399
Since GLib files are only meant to be built as part of GLib, config.h always exists, so the checks are more or less pointless. https://bugzilla.gnome.org/show_bug.cgi?id=793399
mentioned in commit 8138246a