diff --git a/tool/m4/_colorize_result_prepare.m4 b/tool/m4/_colorize_result_prepare.m4
index af572caa18..cc2bbaa703 100644
--- a/tool/m4/_colorize_result_prepare.m4
+++ b/tool/m4/_colorize_result_prepare.m4
@@ -2,12 +2,12 @@
 AC_DEFUN([_COLORIZE_RESULT_PREPARE], [
     msg_checking= msg_result_yes= msg_result_no= msg_result_other= msg_reset=
     AS_CASE(["x${CONFIGURE_TTY}"],
-      [xyes|xalways],[rb_cv_configure_tty=1],
-      [xno|xnever],  [rb_cv_configure_tty=0],
+      [xyes|xalways],[configure_tty=1],
+      [xno|xnever],  [configure_tty=0],
                      [AS_IF([test -t 1],
-                       [rb_cv_configure_tty=1],
-                       [rb_cv_configure_tty=0])])
-    AS_IF([test $rb_cv_configure_tty -eq 1], [
+                       [configure_tty=1],
+                       [configure_tty=0])])
+    AS_IF([test $configure_tty -eq 1], [
 	msg_begin="`tput smso 2>/dev/null`"
 	AS_CASE(["$msg_begin"], ['@<:@'*m],
 	    [msg_begin="`echo "$msg_begin" | sed ['s/[0-9]*m$//']`"