GLib error in www/firefox and www/seamonkey

[Beeblebrox]

Update to the previous update.

While there was a devel/glib20 error, it has now been fixed and all other
apps run without problems, with the exception of firefox & seamonkey.

* ~/.mozilla moved for testing (so empty .mozilla).
* Webkits on host:  py27-qt4-webkit-4.10.3, qt4-webkit-4.8.5_1,
webkit-gtk2-1.8.3_4, webkit-gtk3-2.0.3
* gdb firefox gives:
Reading symbols from /usr/local/lib/firefox/firefox...(no debugging symbols
found)...done. Starting program: /usr/local/bin/firefox
[New LWP 100452],  [New Thread 801802400 (LWP 100452)]

(process:52945): GLib-CRITICAL **: void g_slice_set_config(GSliceConfig,
gint64): assertion 'sys_page_size == 0' failed
(firefox:52945): GLib-GObject-WARNING **: Attempt to add property
GnomeProgram::sm-connect after class was initialised
(firefox:52945): GLib-GObject-WARNING **: Attempt to add property
GnomeProgram::show-crash-dialog after class was initialised
(firefox:52945): GLib-GObject-WARNING **: Attempt to add property
GnomeProgram::display after class was initialised
(firefox:52945): GLib-GObject-WARNING **: Attempt to add property
GnomeProgram::default-icon after class was initialised
[New Thread 830dd5000 (LWP 101567 StreamTrans #2)]
[New Thread 81a945800 (LWP 101563 DOM Worker)]
Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 801802400 (LWP 100452)]
0x0000000803a112a0 in ?? () from /usr/local/lib/firefox/libxul.so
(gdb)

* Options for www/libxul are:  SET+=DBUS, SET+=GIO, SET+=GSTREAMER,
SET+=OPTIMIZED_CFLAGS, SET+=PULSEAUDIO
UNSET+=DEBUG, UNSET+=GCONF, UNSET+=GNOMEUI, UNSET+=GNOMEVFS2,
UNSET+=LIBPROXY, UNSET+=LOGGING, UNSET+=PGO, UNSET+=PROFILE, UNSET+=TEST,
UNSET+=ALSA

Please advise where I should go from here? Is it worth setting/unsetting
some flags and re-building libxul?

Regards.
-- 
FreeBSD_amd64_11-current_RadeonKMS