Restore -DTERMIO/-DTERMIOS on Windows platforms.

The previous defaulting to TERMIOS took away -DTERMIOS / -DTERMIO a
bit too enthusiastically.  Windows/DOSish platforms of all sorts get
identified as OPENSSL_SYS_MSDOS, and they get a different treatment
altogether UNLESS -DTERMIO or -DTERMIOS is explicitely given with the
configuration.  The answer is to restore those macro definitions for
the affected configuration targets.

Reviewed-by: Tim Hudson <tjh@openssl.org>