diff --git a/acinclude.m4 b/acinclude.m4
index b621923ef398e972e75befba1f6547b0b41659f8..71ae301849427529d2f6ab76ddf886451ae48047 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -2,7 +2,7 @@
 
 AC_DEFUN([AST_GCC_ATTRIBUTE],
 [
-AC_MSG_CHECKING(checking for compiler 'attribute $1' support)
+AC_MSG_CHECKING(for compiler 'attribute $1' support)
 AC_COMPILE_IFELSE(
 	AC_LANG_PROGRAM([static int __attribute__(($1)) test(void) {}],
 			[]),
diff --git a/configure b/configure
index 6d297c3647016420b5a61c464b8ca3784eb69cde..86fa048be207fd568b266e42960951b9f1b1296a 100755
--- a/configure
+++ b/configure
@@ -1,5 +1,5 @@
 #! /bin/sh
-# From configure.ac Revision: 41133 .
+# From configure.ac Revision: 41181 .
 # Guess values for system-dependent variables and create Makefiles.
 # Generated by GNU Autoconf 2.60.
 #
@@ -13546,8 +13546,8 @@ fi
 done
 
 
-{ echo "$as_me:$LINENO: checking checking for compiler atomic operations" >&5
-echo $ECHO_N "checking checking for compiler atomic operations... $ECHO_C" >&6; }
+{ echo "$as_me:$LINENO: checking for compiler atomic operations" >&5
+echo $ECHO_N "checking for compiler atomic operations... $ECHO_C" >&6; }
 cat >conftest.$ac_ext <<_ACEOF
 /* confdefs.h.  */
 _ACEOF
@@ -13617,8 +13617,8 @@ rm -f core conftest.err conftest.$ac_objext \
       conftest$ac_exeext conftest.$ac_ext
 
 
-{ echo "$as_me:$LINENO: checking checking for compiler 'attribute pure' support" >&5
-echo $ECHO_N "checking checking for compiler 'attribute pure' support... $ECHO_C" >&6; }
+{ echo "$as_me:$LINENO: checking for compiler 'attribute pure' support" >&5
+echo $ECHO_N "checking for compiler 'attribute pure' support... $ECHO_C" >&6; }
 cat >conftest.$ac_ext <<_ACEOF
 /* confdefs.h.  */
 _ACEOF
@@ -13686,8 +13686,8 @@ fi
 rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 
 
-{ echo "$as_me:$LINENO: checking checking for compiler 'attribute malloc' support" >&5
-echo $ECHO_N "checking checking for compiler 'attribute malloc' support... $ECHO_C" >&6; }
+{ echo "$as_me:$LINENO: checking for compiler 'attribute malloc' support" >&5
+echo $ECHO_N "checking for compiler 'attribute malloc' support... $ECHO_C" >&6; }
 cat >conftest.$ac_ext <<_ACEOF
 /* confdefs.h.  */
 _ACEOF
@@ -13755,8 +13755,8 @@ fi
 rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 
 
-{ echo "$as_me:$LINENO: checking checking for compiler 'attribute const' support" >&5
-echo $ECHO_N "checking checking for compiler 'attribute const' support... $ECHO_C" >&6; }
+{ echo "$as_me:$LINENO: checking for compiler 'attribute const' support" >&5
+echo $ECHO_N "checking for compiler 'attribute const' support... $ECHO_C" >&6; }
 cat >conftest.$ac_ext <<_ACEOF
 /* confdefs.h.  */
 _ACEOF
@@ -13824,8 +13824,8 @@ fi
 rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 
 
-{ echo "$as_me:$LINENO: checking checking for compiler 'attribute unused' support" >&5
-echo $ECHO_N "checking checking for compiler 'attribute unused' support... $ECHO_C" >&6; }
+{ echo "$as_me:$LINENO: checking for compiler 'attribute unused' support" >&5
+echo $ECHO_N "checking for compiler 'attribute unused' support... $ECHO_C" >&6; }
 cat >conftest.$ac_ext <<_ACEOF
 /* confdefs.h.  */
 _ACEOF
@@ -13893,8 +13893,8 @@ fi
 rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 
 
-{ echo "$as_me:$LINENO: checking checking for compiler 'attribute always_inline' support" >&5
-echo $ECHO_N "checking checking for compiler 'attribute always_inline' support... $ECHO_C" >&6; }
+{ echo "$as_me:$LINENO: checking for compiler 'attribute always_inline' support" >&5
+echo $ECHO_N "checking for compiler 'attribute always_inline' support... $ECHO_C" >&6; }
 cat >conftest.$ac_ext <<_ACEOF
 /* confdefs.h.  */
 _ACEOF
@@ -13962,8 +13962,8 @@ fi
 rm -f core conftest.err conftest.$ac_objext conftest.$ac_ext
 
 
-{ echo "$as_me:$LINENO: checking checking for -ffunction-sections support" >&5
-echo $ECHO_N "checking checking for -ffunction-sections support... $ECHO_C" >&6; }
+{ echo "$as_me:$LINENO: checking for -ffunction-sections support" >&5
+echo $ECHO_N "checking for -ffunction-sections support... $ECHO_C" >&6; }
 saved_CFLAGS="${CFLAGS}"
 CFLAGS="${CFLAGS} -ffunction-sections"
 cat >conftest.$ac_ext <<_ACEOF
@@ -14019,8 +14019,8 @@ eval "echo \"\$as_me:$LINENO: $ac_try_echo\"") >&5
 echo "${ECHO_T}yes" >&6; }
 	saved_LDFLAGS="${LDFLAGS}"
 	LDFLAGS="${LDFLAGS} -Wl,--gc-sections"
-	{ echo "$as_me:$LINENO: checking checking for --gc-sections support" >&5
-echo $ECHO_N "checking checking for --gc-sections support... $ECHO_C" >&6; }
+	{ echo "$as_me:$LINENO: checking for --gc-sections support" >&5
+echo $ECHO_N "checking for --gc-sections support... $ECHO_C" >&6; }
 	cat >conftest.$ac_ext <<_ACEOF
 /* confdefs.h.  */
 _ACEOF
@@ -14100,8 +14100,8 @@ CFLAGS="${saved_CFLAGS}"
 
 
 
-{ echo "$as_me:$LINENO: checking checking for res_ninit" >&5
-echo $ECHO_N "checking checking for res_ninit... $ECHO_C" >&6; }
+{ echo "$as_me:$LINENO: checking for res_ninit" >&5
+echo $ECHO_N "checking for res_ninit... $ECHO_C" >&6; }
 cat >conftest.$ac_ext <<_ACEOF
 /* confdefs.h.  */
 _ACEOF
@@ -14170,8 +14170,8 @@ fi
 rm -f core conftest.err conftest.$ac_objext \
       conftest$ac_exeext conftest.$ac_ext
 
-{ echo "$as_me:$LINENO: checking checking for RTLD_NOLOAD" >&5
-echo $ECHO_N "checking checking for RTLD_NOLOAD... $ECHO_C" >&6; }
+{ echo "$as_me:$LINENO: checking for RTLD_NOLOAD" >&5
+echo $ECHO_N "checking for RTLD_NOLOAD... $ECHO_C" >&6; }
 cat >conftest.$ac_ext <<_ACEOF
 /* confdefs.h.  */
 _ACEOF
@@ -16869,8 +16869,8 @@ if test "${USE_IMAP_TK}" != "no"; then
    if test "${IMAP_TK_DIR}" = ""; then
       IMAP_TK_DIR=`pwd`"/../imap-2004g"
    fi
-   { echo "$as_me:$LINENO: checking checking for UW IMAP Toolkit c-client library" >&5
-echo $ECHO_N "checking checking for UW IMAP Toolkit c-client library... $ECHO_C" >&6; }
+   { echo "$as_me:$LINENO: checking for UW IMAP Toolkit c-client library" >&5
+echo $ECHO_N "checking for UW IMAP Toolkit c-client library... $ECHO_C" >&6; }
    saved_cppflags="${CPPFLAGS}"
    saved_libs="${LIBS}"
    if test -f ${IMAP_TK_DIR}/c-client/LDFLAGS ; then
@@ -17142,8 +17142,8 @@ ac_compiler_gnu=$ac_cv_cxx_compiler_gnu
 
 
 if test "${USE_KDE}" != "no"; then
-   { echo "$as_me:$LINENO: checking checking for crashHandler in -lkdecore" >&5
-echo $ECHO_N "checking checking for crashHandler in -lkdecore... $ECHO_C" >&6; }
+   { echo "$as_me:$LINENO: checking for crashHandler in -lkdecore" >&5
+echo $ECHO_N "checking for crashHandler in -lkdecore... $ECHO_C" >&6; }
    saved_libs="${LIBS}"
    saved_cppflags="${CPPFLAGS}"
    CPPFLAGS="${CPPFLAGS} -I${KDE_DIR}/include"
@@ -23899,8 +23899,8 @@ fi
 
 PLATFORM_PTLIB="ptlib_${OSTYPE}_${MACHTYPE}_r"
 if test "${USE_PWLIB}" != "no"; then
-   { echo "$as_me:$LINENO: checking checking for existence of pwlib" >&5
-echo $ECHO_N "checking checking for existence of pwlib... $ECHO_C" >&6; }
+   { echo "$as_me:$LINENO: checking for existence of pwlib" >&5
+echo $ECHO_N "checking for existence of pwlib... $ECHO_C" >&6; }
 
    saved_cppflags="${CPPFLAGS}"
    saved_libs="${LIBS}"
@@ -24012,8 +24012,8 @@ ac_compiler_gnu=$ac_cv_cxx_compiler_gnu
 
 
 if test "${USE_QT}" != "no"; then
-   { echo "$as_me:$LINENO: checking checking for QDate in -lqt" >&5
-echo $ECHO_N "checking checking for QDate in -lqt... $ECHO_C" >&6; }
+   { echo "$as_me:$LINENO: checking for QDate in -lqt" >&5
+echo $ECHO_N "checking for QDate in -lqt... $ECHO_C" >&6; }
    saved_libs="${LIBS}"
    saved_cppflags="${CPPFLAGS}"
    if test "x${QT_DIR}" != "x"; then
@@ -28469,8 +28469,8 @@ ac_compiler_gnu=$ac_cv_cxx_compiler_gnu
 
 
 if test "${USE_VPB}" != "no"; then
-   { echo "$as_me:$LINENO: checking checking for vpb_open in -lvpb" >&5
-echo $ECHO_N "checking checking for vpb_open in -lvpb... $ECHO_C" >&6; }
+   { echo "$as_me:$LINENO: checking for vpb_open in -lvpb" >&5
+echo $ECHO_N "checking for vpb_open in -lvpb... $ECHO_C" >&6; }
    saved_libs="${LIBS}"
    saved_cppflags="${CPPFLAGS}"
    if test "x${VPB_DIR}" != "x"; then
@@ -29046,8 +29046,8 @@ fi
 
 
 if test "${USE_ZAPTEL}" != "no"; then
-   { echo "$as_me:$LINENO: checking checking for zt_transcode_header in zaptel.h" >&5
-echo $ECHO_N "checking checking for zt_transcode_header in zaptel.h... $ECHO_C" >&6; }
+   { echo "$as_me:$LINENO: checking for ZT_TONE_DTMF_BASE in zaptel.h" >&5
+echo $ECHO_N "checking for ZT_TONE_DTMF_BASE in zaptel.h... $ECHO_C" >&6; }
    saved_cppflags="${CPPFLAGS}"
    if test "x${ZAPTEL_DIR}" != "x"; then
       CPPFLAGS="${CPPFLAGS} -I${ZAPTEL_DIR}/include"
@@ -29063,7 +29063,7 @@ cat >>conftest.$ac_ext <<_ACEOF
 int
 main ()
 {
-struct zt_transcode_header test;
+int foo = ZT_TONE_DTMF_BASE;
   ;
   return 0;
 }
diff --git a/configure.ac b/configure.ac
index 46662e69859eaf27271301d271edaa1ed64a82bf..aba1b983726bf318e4769fab5b5a1e39e0d08cc0 100644
--- a/configure.ac
+++ b/configure.ac
@@ -241,7 +241,7 @@ AC_FUNC_UTIME_NULL
 AC_FUNC_VPRINTF
 AC_CHECK_FUNCS([atexit bzero dup2 endpwent floor ftruncate getcwd gethostbyname gethostname gettimeofday inet_ntoa isascii localtime_r memchr memmove memset mkdir munmap pow putenv re_comp regcomp rint select setenv socket sqrt strcasecmp strchr strcspn strdup strerror strncasecmp strndup strnlen strrchr strsep strspn strstr strtol unsetenv utime strtoq strcasestr asprintf vasprintf])
 
-AC_MSG_CHECKING(checking for compiler atomic operations)
+AC_MSG_CHECKING(for compiler atomic operations)
 AC_LINK_IFELSE(
 AC_LANG_PROGRAM([], [int foo1; int foo2 = __sync_fetch_and_add(&foo1, 1);]),
 AC_MSG_RESULT(yes)
@@ -255,7 +255,7 @@ AST_GCC_ATTRIBUTE(const)
 AST_GCC_ATTRIBUTE(unused)
 AST_GCC_ATTRIBUTE(always_inline)
 
-AC_MSG_CHECKING(checking for -ffunction-sections support)
+AC_MSG_CHECKING(for -ffunction-sections support)
 saved_CFLAGS="${CFLAGS}"
 CFLAGS="${CFLAGS} -ffunction-sections"
 AC_COMPILE_IFELSE(
@@ -263,7 +263,7 @@ AC_COMPILE_IFELSE(
 	AC_MSG_RESULT(yes)
 	[saved_LDFLAGS="${LDFLAGS}"]
 	[LDFLAGS="${LDFLAGS} -Wl,--gc-sections"]
-	AC_MSG_CHECKING(checking for --gc-sections support)
+	AC_MSG_CHECKING(for --gc-sections support)
 	AC_LINK_IFELSE(
 		AC_LANG_PROGRAM([], [int x = 1;]),
 		AC_MSG_RESULT(yes)
@@ -278,7 +278,7 @@ CFLAGS="${saved_CFLAGS}"
 AC_SUBST(GC_CFLAGS)
 AC_SUBST(GC_LDFLAGS)
 
-AC_MSG_CHECKING(checking for res_ninit)
+AC_MSG_CHECKING(for res_ninit)
 AC_LINK_IFELSE(
 	AC_LANG_PROGRAM([#include <resolv.h>],
 			[int foo = res_ninit(NULL);]),
@@ -287,7 +287,7 @@ AC_LINK_IFELSE(
 	AC_MSG_RESULT(no)
 )
 
-AC_MSG_CHECKING(checking for RTLD_NOLOAD)
+AC_MSG_CHECKING(for RTLD_NOLOAD)
 AC_LINK_IFELSE(
 	AC_LANG_PROGRAM([#include <dlfcn.h>],
 			[int foo = RTLD_NOLOAD;]),
@@ -355,7 +355,7 @@ if test "${USE_IMAP_TK}" != "no"; then
    if test "${IMAP_TK_DIR}" = ""; then
       IMAP_TK_DIR=`pwd`"/../imap-2004g"
    fi
-   AC_MSG_CHECKING(checking for UW IMAP Toolkit c-client library)
+   AC_MSG_CHECKING(for UW IMAP Toolkit c-client library)
    saved_cppflags="${CPPFLAGS}"
    saved_libs="${LIBS}"
    if test -f ${IMAP_TK_DIR}/c-client/LDFLAGS ; then
@@ -501,7 +501,7 @@ fi
 AC_LANG_PUSH(C++)
 
 if test "${USE_KDE}" != "no"; then
-   AC_MSG_CHECKING(checking for crashHandler in -lkdecore)
+   AC_MSG_CHECKING(for crashHandler in -lkdecore)
    saved_libs="${LIBS}"
    saved_cppflags="${CPPFLAGS}"
    CPPFLAGS="${CPPFLAGS} -I${KDE_DIR}/include"
@@ -682,7 +682,7 @@ AST_EXT_LIB_CHECK([PRI], [pri], [pri_call], [libpri.h])
 
 PLATFORM_PTLIB="ptlib_${OSTYPE}_${MACHTYPE}_r"
 if test "${USE_PWLIB}" != "no"; then
-   AC_MSG_CHECKING(checking for existence of pwlib)
+   AC_MSG_CHECKING(for existence of pwlib)
 	
    saved_cppflags="${CPPFLAGS}"
    saved_libs="${LIBS}"
@@ -726,7 +726,7 @@ fi
 AC_LANG_PUSH(C++)
 
 if test "${USE_QT}" != "no"; then
-   AC_MSG_CHECKING(checking for QDate in -lqt)
+   AC_MSG_CHECKING(for QDate in -lqt)
    saved_libs="${LIBS}"
    saved_cppflags="${CPPFLAGS}"
    if test "x${QT_DIR}" != "x"; then
@@ -833,7 +833,7 @@ AST_EXT_LIB_CHECK([VORBIS], [vorbis], [vorbis_info_init], [vorbis/codec.h], [-lm
 AC_LANG_PUSH(C++)
 
 if test "${USE_VPB}" != "no"; then
-   AC_MSG_CHECKING(checking for vpb_open in -lvpb)
+   AC_MSG_CHECKING(for vpb_open in -lvpb)
    saved_libs="${LIBS}"
    saved_cppflags="${CPPFLAGS}"
    if test "x${VPB_DIR}" != "x"; then
@@ -883,7 +883,7 @@ AC_LANG_POP
 AST_EXT_LIB_CHECK([ZLIB], [z], [compress], [zlib.h])
 
 if test "${USE_ZAPTEL}" != "no"; then
-   AC_MSG_CHECKING(checking for zt_transcode_header in zaptel.h)
+   AC_MSG_CHECKING(for ZT_TONE_DTMF_BASE in zaptel.h)
    saved_cppflags="${CPPFLAGS}"
    if test "x${ZAPTEL_DIR}" != "x"; then
       CPPFLAGS="${CPPFLAGS} -I${ZAPTEL_DIR}/include"
@@ -892,7 +892,7 @@ if test "${USE_ZAPTEL}" != "no"; then
 	[
 	AC_LANG_PROGRAM(
 	[#include <zaptel/zaptel.h>],
-	[struct zt_transcode_header test;])
+	[int foo = ZT_TONE_DTMF_BASE;])
 	],
 	[	AC_MSG_RESULT(yes) 
 		ac_cv_zaptel_h="yes"