[ekiga] Check for ptlib mandatory video support

[Eugen Dedu <ededu src gnome org>]

commit 5e753867bcf6c485fbf8ba1050f8d28c913b30b8
Author: Eugen Dedu <Eugen Dedu pu-pm univ-fcomte fr>
Date:   Tue Apr 2 10:09:51 2013 +0200

    Check for ptlib mandatory video support
    
    Closes bug #696761.

 configure.ac |    8 ++++++++
 1 files changed, 8 insertions(+), 0 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index bae6b8f..977b323 100644
--- a/configure.ac
+++ b/configure.ac
@@ -721,6 +721,14 @@ if test "x$PTLIB_EXPAT" != "xyes"; then
   AC_MSG_ERROR([You need ptlib expat support to compile ekiga])
 fi
 
+# video support is mandatory (too many changes in ekiga to support without video)
+AC_MSG_CHECKING(for PTLIB support for video)
+PTLIB_VIDEO=`$PKG_CONFIG ptlib --variable=PTLIB_VIDEO`
+AC_MSG_RESULT($PTLIB_VIDEO)
+if test "x$PTLIB_VIDEO" != "xyes"; then
+  AC_MSG_ERROR([You need ptlib video support to compile ekiga])
+fi
+
 SUFFIX=
 AC_ARG_ENABLE([opal-debug],
               [AS_HELP_STRING([--enable-opal-debug],[link to debug versions of opal and ptlib (opal_d and 
ptlib_d) (default is disabled)])],