[empathy] Revert "configure: simplify error path in --enable-call"

[Will Thompson <wjt src gnome org>]

commit f3c4f721b13f08c81ff2c9efe5b0f91c07df6903
Author: Will Thompson <will thompson collabora co uk>
Date:   Thu Aug 25 16:17:11 2011 +0100

    Revert "configure: simplify error path in --enable-call"
    
    This reverts commit a7c8e72c9c4daa5a4830bad4ab6baa500106b3b4. It
    accidentally made not specifying an option equivalent to --enable-call.

 configure.ac |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index b7e9b38..cb60cf5 100644
--- a/configure.ac
+++ b/configure.ac
@@ -218,7 +218,7 @@ if test "x$enable_call" != "xno" ; then
       clutter-1.0
       clutter-gtk-1.0
       clutter-gst-1.0
-   ], have_call="yes" )
+   ], have_call="yes", have_call="no" )
 
    if test "x$have_call" = "xyes"; then
       AC_DEFINE(HAVE_CALL, 1, [Define if you have Call channel support])
@@ -227,6 +227,9 @@ else
   have_call=no
 fi
 
+if test "x$enable_call" = "xyes" -a "x$have_call" != "xyes"; then
+   AC_MSG_ERROR([Could not find Call handler dependencies.])
+fi
 AM_CONDITIONAL(HAVE_CALL, test "x$have_call" = "xyes")