diff --git a/configure.in b/configure.in
index e461658..48fa694 100644
--- a/configure.in
+++ b/configure.in
@@ -2486,6 +2486,17 @@
   [Define if WINDOW in curses.h offers a field _flags.])
 fi
 
+AC_MSG_CHECKING(for /dev/ptmx)
+
+if test -e /dev/ptmx
+then
+  AC_MSG_RESULT(yes)
+  AC_DEFINE(HAVE_DEV_PTMX, 1,
+  [Define if we have /dev/ptmx.])
+else
+  AC_MSG_RESULT(no)
+fi
+
 AC_CHECK_TYPE(socklen_t,,
   AC_DEFINE(socklen_t,int,
             Define to `int' if <sys/socket.h> does not define.),[