diff --git a/crypto/ec/ec_test.c b/crypto/ec/ec_test.c
index 9ef98977..8d53f878 100644
--- a/crypto/ec/ec_test.c
+++ b/crypto/ec/ec_test.c
@@ -13,7 +13,7 @@
  * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
 
 #include <stdio.h>
-#include <unistd.h>
+#include <string.h>
 
 #include <openssl/bio.h>
 #include <openssl/crypto.h>