asterisk users - Apr 2006 - New backport of T.38 fax passthrough functionality to asterisk-1.2.7.1

(This is a shameless copy-paste from the note I posted on 
http://bugs.digium.com/view.php?id=5090)

I have again backported the whole T.38 shebang to the stable branch.  The port
was
based on two versions of the t38passthrough branch: r19125, the latest 
unconflicted automerge, and r13623, the latest version without the new chan_sip 
flag structure.  Basically, the port contains everything that matters, EXCEPT:

* chan_sip.c: r15282, new flag structure (not the point of this backport)
* chan_sip.c: r15329, handle_common_options for the T.38 stuff (due to lack of
new
flag structure)
* chan_sip.c: PCAddach's sip-t38-5.diff or simishag's t38-19892 (it was
a
non-issue in stable).
* udptl.c: PCAddach's udptl-resend.diff (the jury's still out on that
one)

Alert 1: I haven't fixed any bugs, just ported the current state of the 
t38passthrough (actually, it's more likely I introduced a bug or two!). 
This is
just so more people can afford to test the code, and thus help this bug move
along.

Alert 2: I also haven't tested this anywhere near enough.  It compiles and
runs,
but that's as far as I got.  Please test more.

Alert 3: For users of my previous 1.2.4 patch, mind that there is no longer a
T38
CFLAG in the Makefile.  T38 support is compiled by default.  Nevertheless, you
can
configure it on a per peer/user basis.

Untarring will create asterisk-1.2.7.1-t38-20060423/.  Copy the files therein to
your out-of-the-box asterisk-1.2.7.1; don't use a checkout with T38 patches 
previously applied, or you'll get conflicts.  And then:

$patch -p0 < asterisk-1.2.7.1-t38-20060423.diff
$make
$make install

Disclaimer: I'm not the author of T.38 support in Asterisk, Steve Underwood
is
(with the help of others such as Olle himself, as you'd see in the
bugtracker).  I
just went through the drudge work of backporting the latest t38passthrough
branch.

I have a question for Olle, though: the t38 branch stopped being automerged to 
trunk a couple few weeks ago; is this intentional?

Thanks,
Adolfo