Merge pull request #12927 from richardkchapman/hpcc22740

HPCC-22740 Build error on osx in cryptolib

Reviewed-by: Gavin Halliday <ghalliday@hpccsystems.com>

plugins/cryptolib/cryptolib.cpp

@@ -22,6 +22,7 @@
 #include <openssl/pem.h>
 #include <openssl/err.h>
 #include <openssl/rand.h>
+#include <string>
 #include <unordered_map>
 
 #include "cryptolib.hpp"