Revision 373830

- Update Thunderbird to 31.3.0
- Update gmp-api to 35.0
- Update openh264 to 1.2
- Update NSS to 3.17.3
- Update Firefox to 34.0.5
- Update Firefox ESR 31.3.0
- Update libxul to 31.3.0
- Improve CONFIGURE_TARGET handling
- Always build using client.mk
- Switch to clang by default on systems without libc++
  (/stable/8 and /stable/9)
- Drop lang/python2 dependency, only lang/python27 is required
  to build
- Use DuckDuckGo searchplugin from upstream (has suggestions
  and purposes)
- Backport a few about:memory fixes
- Backport Web Notifications libnotify integration
- Add GTK3 option for www/firefox. Adwaita is a bit broken
  since Gtk 3.14, see:
  https://bugzilla.mozilla.org/show_bug.cgi?id=1073117

PR:		195559
Submitted by:	Jan Beich
MFH:		2014Q4
Security:	http://vuxml.org/freebsd/7ae61870-9dd2-4884-a2f2-f19bb5784d09.html