Update to thunderbird 17.0.2/enigmail 1.5.0.

Next major release will be tb 24, in synch with fx 24 - we track the
stable/bugfix releases (which are not ESR. Not sure this is very
clear..) Users interested in testing the beta releases (tracking fx
betas) can grab them from my git tree.

- Fixes MFSA 2013-01 -> 20
- remove enigmail genxpi patch, and to a SUBST_VARS dance with an
  XPCOM_ABI variable for the consistent naming of the new internal
libsuprocess ipc lib.
- add an enigmail patch to link with -shared, and remove a -Woption not
  recognized by our gcc.

Written by: Landry Breuil <landry@openbsd.org>

Conflicts:
	mail/mozilla-thunderbird/pkg/PLIST-enigmail
Build Seamonkey and Firefox with gcc on i386 due to segfaults with the
CLang build (seems to be connected with opening pages using JavaScript).
Bump REVISIONs.

Written by: Stuart Henderson <sthen@openbsd.org>