1 files changed, 1 insertions, 1 deletions
diff --git a/eval.c b/eval.c
index b98746e517..fd7a209aff 100644
--- a/eval.c
+++ b/eval.c
@@ -9546,7 +9546,7 @@ enum thread_status {
 # endif
 #endif
 
-#ifdef NFDBITS
+#if defined(NFDBITS) && defined(howmany)
 void
 rb_fd_init(fds)
     volatile rb_fdset_t *fds;