- Compilation fix from Kiyokazu SUTO <suto@ks-and-ks.ne.jp>
 - Fixed broken bugfix for /dev/ptmx on Linux systems which lack
   openpty(). Report from Kiyokazu SUTO <suto@ks-and-ks.ne.jp>
diff --git a/configure.in b/configure.in
index 816f56e..a5a97e7 100644
--- a/configure.in
+++ b/configure.in
@@ -507,7 +507,7 @@
 	]
 )
 
-if test ! -z "$no_dev_ptmx" ; then
+if test -z "$no_dev_ptmx" ; then
 	AC_CHECK_FILE("/dev/ptmx", AC_DEFINE_UNQUOTED(HAVE_DEV_PTMX))
 fi
 AC_CHECK_FILE("/dev/ptc", AC_DEFINE_UNQUOTED(HAVE_DEV_PTS_AND_PTC))