diff --git a/crypto/bio/bss_bio.c b/crypto/bio/bss_bio.c
index 74902bb1d805c980d49a7788019646b37211722a..cff55bfa8902c96932e78139025e7365fdd6ce57 100644
--- a/crypto/bio/bss_bio.c
+++ b/crypto/bio/bss_bio.c
@@ -16,6 +16,7 @@
 #include <limits.h>
 #include <stdlib.h>
 #include <string.h>
+#include <sys/types.h>
 
 #include <openssl/bio.h>
 #include <openssl/err.h>