Detect other instances of the obs by creating an extra dummy thread,
named "OBS runonce". The process of threads enumeration of current user
is guarded by an O_EXLOCK file advisory lock when opening the lock file.
Such file lock would be dropped once the thread name is changed.
This should be usable on FreeBSD and possibly compile on DragonFly BSD.
fixes: #3053
Code submissions have continually suffered from formatting
inconsistencies that constantly have to be addressed. Using
clang-format simplifies this by making code formatting more consistent,
and allows automation of the code formatting so that maintainers can
focus more on the code itself instead of code formatting.
All of the monitor discovery logic can be implemented with Qt. This
change removes all the x11 implementations in favor of Qt and removes a
fair amount of platform specific code.
