diff --git a/contrib/mandoc/config.h b/contrib/mandoc/config.h
index 553c4c8b740..213513f1c87 100644
--- a/contrib/mandoc/config.h
+++ b/contrib/mandoc/config.h
@@ -13,7 +13,11 @@
 #define HAVE_ENDIAN 0
 #define HAVE_ERR 1
 #define HAVE_FTS 1
+#ifdef __GLIBC__
+#define HAVE_FTS_COMPARE_CONST 0
+#else
 #define HAVE_FTS_COMPARE_CONST 1
+#endif
 #define HAVE_GETLINE 1
 #define HAVE_GETSUBOPT 1
 #define HAVE_ISBLANK 1