OpenBSD has intypes.h

Update e_os2.h so that inttypes.h is included.

RT4378
Reviewed-by: NRichard Levitte <levitte@openssl.org>

include/openssl/e_os2.h

@@ -245,7 +245,7 @@ typedef UINT64 uint64_t;
 #  define PRIu64 "%Lu"
 # elif (defined(__STDC_VERSION__) && __STDC_VERSION__ >= 199901L) || \
      defined(__osf__) || defined(__sgi) || defined(__hpux) || \
-     defined(OPENSSL_SYS_VMS)
+     defined(OPENSSL_SYS_VMS) || defined (__OpenBSD__)
 #  include <inttypes.h>
 # elif defined(_MSC_VER) && _MSC_VER<=1500
 /*