AM_CONDITIONAL(ENABLE_ACM, test "x$ENABLE_ACM" = "xyes")
dnl end --------------------------------------------------------------------
+dnl use aec ----------------------------------------------------------------
+AC_ARG_ENABLE(aec, AC_HELP_STRING([--enable-aec], [using aec]),
+[
+ case "${enableval}" in
+ yes) ENABLE_AEC=yes ;;
+ no) ENABLE_AEC=no ;;
+ *) AC_MSG_ERROR(bad value ${enableval} for --enable-aec) ;;
+ esac
+ ],[USE_AEC=no])
+AM_CONDITIONAL(ENABLE_AEC, test "x$ENABLE_AEC" = "xyes")
+dnl end --------------------------------------------------------------------
+
#### D-Bus support (optional) ####
AC_ARG_ENABLE([dbus],