diff --git a/crypto/err/err.h b/crypto/err/err.h
index 76a8ed1b3..519a9c5b0 100644
--- a/crypto/err/err.h
+++ b/crypto/err/err.h
@@ -61,6 +61,7 @@
 
 #ifndef NO_FP_API
 #include <stdio.h>
+#include <stdlib.h>
 #endif
 
 #ifdef	__cplusplus