updated for version 7.2-159
diff --git a/src/configure.in b/src/configure.in
index ff1bd0c..6821417 100644
--- a/src/configure.in
+++ b/src/configure.in
@@ -2952,7 +2952,7 @@
 if test "$enable_multibyte" = "yes"; then
   cflags_save=$CFLAGS
   ldflags_save=$LDFLAGS
-  if test -n "$x_includes" ; then
+  if test "x$x_includes" != "xNONE" ; then
     CFLAGS="$CFLAGS -I$x_includes"
     LDFLAGS="$X_LIBS $LDFLAGS -lX11"
     AC_MSG_CHECKING(whether X_LOCALE needed)