Merge branch 'yamt/erl_driver-ssize_t/OTP-10699'

* yamt/erl_driver-ssize_t/OTP-10699:
  Use correct way to pull the definition of ssize_t

Author: psyeugenic

erts/emulator/beam/erl_driver.h

@@ -85,7 +85,7 @@
 #include "erl_drv_nif.h"
 
 #include <stdlib.h>
-#include <string.h>		/* ssize_t on Mac OS X */
+#include <sys/types.h>	/* ssize_t */
 
 #if defined(__WIN32__) || defined(_WIN32) || defined(_WIN32_)
 #ifndef STATIC_ERLANG_DRIVER