Ensure PBX_DAHDI_TRANSCODE will evaluate to 0 if not found instead of empty.

pointed out by tzafrir on #asterisk-dev


git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.4@136999 65c4cc65-6c06-0410-ace0-fbb531ad65f3

configure

@@ -1,5 +1,5 @@
 #! /bin/sh
-# From configure.ac Revision: 134649 .
+# From configure.ac Revision: 136560 .
 # Guess values for system-dependent variables and create Makefiles.
 # Generated by GNU Autoconf 2.61 for asterisk 1.4.
 #
@@ -17146,6 +17146,7 @@ fi
 
 fi
 
+PBX_DAHDI_TRANSCODE=0
 if test "${USE_DAHDI}" != "no" ; then
 
     if test "x${PBX_DAHDI}" != "x1"; then

configure.ac

@@ -438,6 +438,7 @@ if test "x${host_os}" = "xlinux-gnu" ; then
   AST_EXT_LIB_CHECK([CAP], [cap], [cap_from_text], [sys/capability.h])
 fi
 
+PBX_DAHDI_TRANSCODE=0
 if test "${USE_DAHDI}" != "no" ; then
 	AST_C_DEFINE_CHECK([DAHDI], [DAHDI_CODE], [dahdi/user.h])
 	if test "x${PBX_DAHDI}" = "x1" ; then