On Windows, the detection changes only by inserting the use of the
environment variable before the existing tests and removing the check on
stderr.
This commit adds logic similar to Windows's: if the application has a
controlling TTY, we'll use stderr. Otherwise, we'll use the system log.
This is technically a change in behavior: previously, we would always
use the system log, unless the environment variable told us not to.
In practice, the behavior doesn't really change: Android and BlackBerry
and systemd-spawned applications are launched with no controlling TTY,
so logging will go to their logging systems.
[ChangeLog][Important behavior changes][Logging (including qDebug and
qWarning)] Log output will now go to the system log (if support for it
was compiled into Qt) if the application has no controlling terminal or
console window. Set QT_LOGGING_TO_CONSOLE to 1 to force logging to go to
stderr.
Task-number: QTCREATORBUG-12564
Change-Id: I043c5c4f47c15f26d4f4a5cf43df466ea38cdbc7
Reviewed-by: Kai Koehne <kai.koehne@digia.com>
cc50651cce