(HAVE_X11XTR6): Arrange to define it.

diff --git a/configure1.in b/configure1.in
index 2e48ca7..080141c 100755 (executable)
--- a/configure1.in
+++ b/configure1.in
@@ -1424,6 +1424,15 @@ if test "${HAVE_X11}" = "yes"; then
 XScreenNumberOfScreen XSetWMProtocols)
 fi
 
+if test "${USE_X_TOOLKIT}" != "none"; then
+  AC_COMPILE_CHECK(X11 toolkit version,
+                  [#include <X11/Intrinsic.h>],
+                  [#if XtSpecificationRelease < 6
+fail;
+#endif],
+                  AC_DEFINE(HAVE_X11XTR6))
+fi
+
 AC_ALLOCA
 
 # logb and frexp are found in -lm on most systems.