child stdout and falls back to plain pipe if openpty fails. Child uses
the 'usepty' flag to decide whether to treat this descriptor as a pty
or as a pipe.
Set 'usepty' flag to 0 upon openpty failure to inform the child that
it isn't dealing with a pty even though pty has been requested.
Thanks to Michal Peclo for reporting it and providing a patch.
cmr:v1.7.3:reviewer=jsquyres
cmr:v1.6.6:reviewer=jsquyres
This commit was SVN r29169.