ftmod_libpri: Bail out with an error message if libpri is too old and selected trunk type is BRI or BRI_PTMP
Signed-off-by: Stefan Knoblich <s.knoblich@axsentis.de>

	compatible with std=c99

Signed-off-by: Stefan Knoblich <s.knoblich@axsentis.de>

Signed-off-by: Stefan Knoblich <s.knoblich@axsentis.de>

Requires libpri-1.4.12_beta1 or newer!
Completely untested, AOC-S/D/E ChargingRequest operations are sent to NT (DTAG BRI PTMP),
but rejected with "Unrecognized Operation".

NOTE: FreeTDM core needs support for this to be useful!
      Only AOC-E events are decoded and sent to the log.

To enable:
    Set (or add) <param name="opts" value="aoc"> in your
    libpri_spans span config.
Signed-off-by: Stefan Knoblich <s.knoblich@axsentis.de>

ftmod_libpri: Write fatal error message during span configuration to console (and to span error log).
Signed-off-by: Stefan Knoblich <s.knoblich@axsentis.de>

"all" and "none" can only be used alone,
other flags are additive.
Signed-off-by: Stefan Knoblich <s.knoblich@axsentis.de>

freetdm: convert ftmod_libpri (+ libpri_spans) to use new ftdm_configure_span_signaling() interface.

This fixes several issues with parameter handling (e.g. default alaw/ulaw selection being totally useless).
Signed-off-by: Stefan Knoblich <s.knoblich@axsentis.de>

Signed-off-by: Stefan Knoblich <s.knoblich@axsentis.de>

Fixes:
- Fix double locking in check_state(): remove ftdm_mutex_(un)lock calls.

New:
- Add lpwrap_init_bri() to initialize libpri in BRI mode
- Use trunk type to determine PRI/BRI and PTP/PTMP mode (no additional configuration required).
- Improve libpri detection code in configure.ac, check whether libpri is usable
  and if BRI support is available (needs more work)

Cleanups:
- Whitespace and indentation cleanups
- Rename str2* functions to parse_*
- Simplify libpri_configure_span() option parsing and bail out on error
- Add "ftdm libpri help" command that displays usage information
- Coding style cleanups and other (minor) changes

Known issues:
- BRI PTMP TE Q.921 link does not go beyond TEI ASSIGNED state,
  SABME requests are ignored by NT (EuroISDN DTAG, DAHDI-2.3.0.1, vzaphfc)
Signed-off-by: Stefan Knoblich <s.knoblich@axsentis.de>

FreeTDM: Update .gitignore, add files shipped with libtool (build/{libtool,lt*}.m4) and compiled test binaries