configScreen used a dynamically allocated buffer for XF86ConfScreenRec
when conf_screen argument was NULL. This pointer was never stored
anywhere, nor was it released, so this patch makes the function use
automatically allocated storage in that situation.
[ajax: minor grammar fix]
Reviewed-by: Adam Jackson <ajax@redhat.com>
Reviewed-by: Rami Ylimäki <rami.ylimaki@vincit.fi>
Signed-off-by: Erkki Seppälä <erkki.seppala@vincit.fi>