Callbacks are invoked from ftdm_span_start/_stop().
I/O is started before SIG and shut down in reverse order.

This is needed for ftmod_misdn, to move the mISDN message handling
into a separate thread (solving the mISDN socket vs. FreeTDM API issues).

With these callbacks, the I/O thread can be started after the span I/O configuration
has been (successfully) completed and stopped before destroying the span.

NOTE: Both SIG and I/O callbacks are called with the span mutex locked,
so threads created or destroyed synchronously in either of the custom
start/stop functions, can not use ftdm_span_*() functions that lock
the span mutex (e.g. ftdm_span_get_channel_count()).
Signed-off-by: Stefan Knoblich <stkn@openisdn.net>

The --enable-builtin-tiff option appends libs/tiff-3.8.2/libtiff/libtiff.la
to LIBS, causing the AC_CHECK_LIB([jpeg]...) check to fail, because
libtiff.la does not exist at configure time.

Temporarily store tiff and jpeg libs in TIFF_-/JPEG_LIBS variables and
append them to LIBS after all library checks have run.

Example error output:
    configure:20049: checking for jpeg_start_compress in -ljpeg
    configure:20074: cc -o conftest -O2 -pipe -fno-strict-aliasing    -L/usr/local/lib conftest.c -ljpeg  -lm  /usr/home/ports/net/freeswitch-core-devel/work/freeswitch-1.2.1/libs/tiff-3.8.2/libtiff/libtiff.la >&5
    cc: /usr/home/ports/net/freeswitch-core-devel/work/freeswitch-1.2.1/libs/tiff-3.8.2/libtiff/libtiff.la: No such file or directory
Signed-off-by: Stefan Knoblich <stkn@openisdn.net>

Fix rtp payload number and possibly other params, since we ALWAYS use PCMU all params should be hardcoded

FreeSWITCH: Add WIN32 strerror_s() variant to custom switch_strerror_r() helper function and fix more strerror_r() users.

Convert mod_xml_cdr, mod_json_cdr and mod_conference to the new function.
Signed-off-by: Stefan Knoblich <stkn@openisdn.net>

GNU variant of strerror_r() returns char *, while the XSI version returns int.

To make things worse, glibc ships both and added a unused result warning
in recent versions (2.16) causing the build to fail.

Add our own custom wrapper that always returns a pointer to the message buffer
and additionally make XSI versions of strerror_r() GNU compatible by
returning "Unknown error xxx" if no error message is available.

Fixes:
    src/switch_rtp.c: In function 'rtp_common_read':
    src/switch_rtp.c:3313:15: error: ignoring return value of 'strerror_r',
    declared with attribute warn_unused_result [-Werror=unused-result]
    cc1: all warnings being treated as errors
Signed-off-by: Stefan Knoblich <stkn@openisdn.net>

Add condition matching capability to only account for one or more subset of channel directions to radius.

A lot of tiny tidy up edits

A bug in end of image handling fixed, which could mean some T.85 images would
screw up.

The len variable can, in certain situations (large burst of incoming non-SLIN audio),
exceed the size of the on-stack frame buffer, which causes ftdm_buffer_read_loop() to
overwrite the dt_buffer pointer.

Use ftdm_min() to make sure len (after conversion to SLIN units) isn't larger
than the frame buffer size.

Also adds are couple more code comments.
Signed-off-by: Stefan Knoblich <stkn@openisdn.net>

combination

Improvements to image flattening in spandsp's image translate code