build(freeswitch): add mod_audio_fork and libwebsockets

Add mod_audio_fork to FreeSWITCH's build alongside libwebsockets
(which mod_audio_fork depends on).

mod_audio_fork is used by the built in transcription feature as
a way to extract L16 streams from FreeSWITCH via WebSockets for further
processing by arbitrary transcription servers.

For full details on mod_audio_fork itself, please check drachtio's
source repo: github.com/drachtio/drachtio-freeswitch-modules.git

A few cautionary tales about this one:
  - The new patch (mod_audio_fork_build.patch) guarantees libwebsockets
    is properly linked to FreeSWITCH and that mod_audio_fork is built as
    well. That's because mod_audio_fork is not an upstream module.
  - The patch _may_ introduce conflicts on FreeSWITCH bumps more easily
    than the other patches we have. They shouldn't be too hard to adapt,
    though.
  - There's fine tuning to be done to FreeSWITCH's unit file regarding
    mod_audio_fork's capabilities. Again: check drachtio's repo.

build/packages-template/bbb-freeswitch-core/build.sh

@@ -73,18 +73,51 @@ cd ..
 
 ldconfig
 
+# libwebsockets start
+# mod_audio_fork needs it (used in built-in speech transcription)
+if [ ! -d libwebsockets ]; then
+  git clone https://github.com/warmcat/libwebsockets.git
+fi
+cd libwebsockets/
+git checkout v3.2.3
+
+mkdir -p build
+cd build
+
+cmake ..
+make -j $(nproc)
+make install
+cd ../../
+
+ldconfig
+# libwebsockets end
+
+# mod_audio_fork start
+# copy mod_audio_fork into place (used in built-in speech transcription)
+if [ ! -d drachtio-freeswitch-modules ]; then
+  git clone https://github.com/drachtio/drachtio-freeswitch-modules.git
+fi
+
+cd drachtio-freeswitch-modules
+git checkout 4198b1c114268829627069afeea7eb40c86a81af
+cp -r modules/mod_audio_fork $BUILDDIR/freeswitch/src/mod/applications/mod_audio_fork
+cd ..
+# mod_audio_fork end
+
 # we already cloned the FS repo in freeswitch.placeholder.sh and selected tag/branch
 
 cd $BUILDDIR/freeswitch
 
 patch -p0 < $BUILDDIR/floor.patch
 patch -p0 --ignore-whitespace < $BUILDDIR/audio.patch       # Provisional patch for https://github.com/signalwire/freeswitch/pull/1531
+# Enables mod_audio_fork in the build process  (used in built-in speech transcription)
+patch -p1 < $BUILDDIR/mod_audio_fork_build.patch
 
-./bootstrap.sh 
+./bootstrap.sh
 
 ./configure --disable-core-odbc-support --disable-core-pgsql-support \
-    --without-python --without-erlang --without-java \
-    --prefix=/opt/freeswitch 
+    --without-python --without-erlang --without-java --with-lws=yes \
+    --prefix=/opt/freeswitch
 
 # Overrides for generating debug version
 #   --prefix=/opt/freeswitch CFLAGS="-Wno-error -Og -ggdb" CXXFLAGS="-Wno-error -Og -ggdb"

build/packages-template/bbb-freeswitch-core/mod_audio_fork_build.patch

@@ -0,0 +1,72 @@
+diff --git a/Makefile.am b/Makefile.am
+index f869072ff7..b31807a6f8 100644
+--- a/Makefile.am
++++ b/Makefile.am
+@@ -166,6 +166,14 @@ if HAVE_FVAD
+ CORE_CFLAGS += -DSWITCH_HAVE_FVAD $(LIBFVAD_CFLAGS)
+ endif
+ 
++##
++## libwebsockets
++##
++if HAVE_LWS
++CORE_CFLAGS += -DSWITCH_HAVE_LWS $(LWS_CFLAGS)
++LWS_LIBS += -lwebsockets
++endif
++
+ ##
+ ## libfreeswitch
+ ##
+@@ -233,7 +241,7 @@ endif
+ lib_LTLIBRARIES	         = libfreeswitch.la
+ libfreeswitch_la_CFLAGS  = $(CORE_CFLAGS) $(SQLITE_CFLAGS) $(GUMBO_CFLAGS) $(FVAD_CFLAGS) $(FREETYPE_CFLAGS) $(CURL_CFLAGS) $(PCRE_CFLAGS) $(SPEEX_CFLAGS) $(LIBEDIT_CFLAGS) $(openssl_CFLAGS) $(SOFIA_SIP_CFLAGS) $(AM_CFLAGS) $(TPL_CFLAGS)
+ libfreeswitch_la_LDFLAGS = -version-info 1:0:0 $(AM_LDFLAGS) $(PLATFORM_CORE_LDFLAGS) -no-undefined
+-libfreeswitch_la_LIBADD  = $(CORE_LIBS) $(APR_LIBS) $(SQLITE_LIBS) $(GUMBO_LIBS) $(FVAD_LIBS) $(FREETYPE_LIBS) $(CURL_LIBS) $(PCRE_LIBS) $(SPEEX_LIBS) $(LIBEDIT_LIBS) $(SYSTEMD_LIBS) $(openssl_LIBS) $(PLATFORM_CORE_LIBS) $(TPL_LIBS) $(SPANDSP_LIBS) $(SOFIA_SIP_LIBS)
++libfreeswitch_la_LIBADD  = $(CORE_LIBS) $(APR_LIBS) $(SQLITE_LIBS) $(GUMBO_LIBS) $(FVAD_LIBS) $(FREETYPE_LIBS) $(CURL_LIBS) $(PCRE_LIBS) $(SPEEX_LIBS) $(LIBEDIT_LIBS) $(SYSTEMD_LIBS) $(openssl_LIBS) $(PLATFORM_CORE_LIBS) $(TPL_LIBS) $(SPANDSP_LIBS) $(SOFIA_SIP_LIBS) $(LWS_LIBS)
+ libfreeswitch_la_DEPENDENCIES = $(BUILT_SOURCES)
+ 
+ if HAVE_PNG
+diff --git a/build/modules.conf.in b/build/modules.conf.in
+index 7bf59e2acc..9cab2f6fdb 100644
+--- a/build/modules.conf.in
++++ b/build/modules.conf.in
+@@ -1,3 +1,4 @@
++applications/mod_audio_fork
+ #applications/mod_abstraction
+ applications/mod_av
+ #applications/mod_avmd
+diff --git a/configure.ac b/configure.ac
+index f09196bdfd..fba7b9d676 100644
+--- a/configure.ac
++++ b/configure.ac
+@@ -1590,6 +1590,22 @@ AS_IF([test "x$enable_core_libedit_support" != "xno"],[
+       AC_MSG_ERROR([You need to either install libedit-dev (>= 2.11) or configure with --disable-core-libedit-support])
+       ])])])
+ 
++dnl ---------------------------------------------------------------------------
++dnl - libwebsockets
++dnl ---------------------------------------------------------------------------
++AC_ARG_WITH(lws,
++  [AS_HELP_STRING([--with-lws],
++     [enable support for libwebsockets])],
++  [with_lws="$withval"],
++  [with_lws="no"])
++if test "$with_lws" = "yes"; then
++  PKG_CHECK_MODULES([LWS], [libwebsockets], [
++    AM_CONDITIONAL([HAVE_LWS],[true])], [
++    AC_MSG_RESULT([no]); AM_CONDITIONAL([HAVE_LWS],[false])])
++else
++    AM_CONDITIONAL([HAVE_LWS],[false])
++fi
++
+ AC_ARG_ENABLE(systemd,
+   [AS_HELP_STRING([--enable-systemd], [Compile with systemd notify support])])
+ 
+@@ -2081,6 +2097,7 @@ AC_CONFIG_FILES([Makefile
+ 		tests/unit/Makefile
+ 		src/Makefile
+ 		src/mod/Makefile
++		src/mod/applications/mod_audio_fork/Makefile
+ 		src/mod/applications/mod_abstraction/Makefile
+ 		src/mod/applications/mod_avmd/Makefile
+ 		src/mod/applications/mod_bert/Makefile

build/packages-template/bbb-freeswitch-core/modules.conf

@@ -52,6 +52,7 @@ applications/mod_valet_parking
 #applications/mod_vmd
 applications/mod_voicemail
 #applications/mod_voicemail_ivr
+applications/mod_audio_fork
 #asr_tts/mod_cepstral
 #asr_tts/mod_flite
 #asr_tts/mod_pocketsphinx