stub out AM_ICONV if it is not available

If we're building on a system w/out gettext, just stub out the AM_ICONV
macro.  This is useful for embedded systems which don't have i18n support
as the current code will auto-disable itself anyways.

configure.ac

@@ -75,6 +75,8 @@ fi
 AC_HEADER_STDC
 AC_CHECK_HEADERS([errno.h limits.h stddef.h stdlib.h string.h unistd.h])
 
+dnl if we're configuring on a system w/out gettext, don't fall over
+m4_ifndef([AM_ICONV],[m4_define([AM_ICONV],[:])])
 AM_ICONV
 # if test -n "$LIBICONV" ; then
 #   LIBS="$LIBS $LIBICONV"