diff --git a/config.h.in b/config.h.in
index ea2f72b..4aa7a2f 100644
--- a/config.h.in
+++ b/config.h.in
@@ -59,9 +59,6 @@
 /* Define to 1 if you have the <unistd.h> header file. */
 #undef HAVE_UNISTD_H
 
-/* Define to 1 if the system has the type `_Bool'. */
-#undef HAVE__BOOL
-
 /* Define to the sub-directory in which libtool stores uninstalled libraries.
    */
 #undef LT_OBJDIR