The ENGINE implementations in ./engines/ should be role models on how to

write external engines (and thus should require only installed openssl
headers and libs to compile without warnings). So this gets rid of recently
introduced compilation warnings (no longer including internal headers) by
including string.h directly.

engines/e_4758_cca.c

@@ -54,6 +54,7 @@
  */
 
 #include <stdio.h>
+#include <string.h>
 #include <openssl/crypto.h>
 /* #include <openssl/pem.h> */
 #include <openssl/dso.h>

engines/e_atalla.c

@@ -57,6 +57,7 @@
  */
 
 #include <stdio.h>
+#include <string.h>
 #include <openssl/crypto.h>
 #include <openssl/buffer.h>
 #include <openssl/dso.h>

engines/e_cswift.c

@@ -57,6 +57,7 @@
  */
 
 #include <stdio.h>
+#include <string.h>
 #include <openssl/crypto.h>
 #include <openssl/buffer.h>
 #include <openssl/dso.h>

engines/e_sureware.c

@@ -51,6 +51,7 @@
 ====================================================================*/
 
 #include <stdio.h>
+#include <string.h>
 #include <openssl/crypto.h>
 #include <openssl/pem.h>
 #include <openssl/dso.h>

engines/e_ubsec.c

@@ -59,6 +59,7 @@
  */
 
 #include <stdio.h>
+#include <string.h>
 #include <openssl/crypto.h>
 #include <openssl/buffer.h>
 #include <openssl/dso.h>