Make sure that disabling the MAYLOSEDATA3 warning is only done when the compiler...

Make sure that disabling the MAYLOSEDATA3 warning is only done when the compiler supports it. Otherwise, there are warnings about it lacking everywhere, which is quite tedious to read through while trying to check for other warnings.

Reviewed-by: Tim Hudson <tjh@openssl.org>
Conflicts:
	ssl/ssl-lib.com