diff --git a/gnu/lib/libstdc++/config.h b/gnu/lib/libstdc++/config.h
index a34d4daeb55d..d764096083bc 100644
--- a/gnu/lib/libstdc++/config.h
+++ b/gnu/lib/libstdc++/config.h
@@ -261,7 +261,7 @@
 #define HAVE_FLOORF 1
 
 /* Define to 1 if you have the `floorl' function. */
-/* #undef HAVE_FLOORL */
+#define HAVE_FLOORL 1
 
 /* Define to 1 if you have the `fmodf' function. */
 #define HAVE_FMODF 1