Include <openssl/err.h> for the ERR_error_string function.  This
improves compatibility with future compilers which will not accept
implicit funcction declarations by default.

diff --git a/configure b/configure
index fe4e606e91010520..694801b2a93659af 100755
--- a/configure
+++ b/configure
@@ -5199,6 +5199,8 @@ else
       cat confdefs.h - <<_ACEOF >conftest.$ac_ext
 /* end confdefs.h.  */
 #include <openssl/ssl.h>
+      #include <openssl/err.h>
+
 int
 main ()
 {
diff --git a/configure.ac b/configure.ac
index 09dbb7a1e8d35c84..abd599c90e3ef0d7 100644
--- a/configure.ac
+++ b/configure.ac
@@ -559,7 +559,9 @@ if test -n "$WITH_OPENSSL" -a "$sc_cv_have_openssl_ssl_h" = 'yes'; then
       else
 	LIBS="$LIBS -lssl -lcrypto"
       fi
-      AC_TRY_LINK([#include <openssl/ssl.h>],
+      AC_TRY_LINK([#include <openssl/ssl.h>
+      #include <openssl/err.h>
+      ],
        [SSL_library_init();ERR_error_string()],
        [sc_cv_have_libssl='yes'],
        [ LIBS="$LIBS -lcrypto"