This has meant very little for a long time as configure.ac just
hardcoded these values depending on the current OS versions at the
time.
The only place where this is really 'needed' is XlationSvc.c in DtSvc
so that differences between locale specifications on various versions
of an OS can be accounted for. So for now, we just define those when
building DtSvc.
We could probably safely remove them as well with an update to the
Xlate locale DB to remove ancient cruft we don't care about anymore.
For various other modules, like dtlogin, dtsession, etc we just use
the code that was already being used due to the hardcoded values we've
had for the last 10-ish years.
The POSIX __linux__ commit broke the special detection on linux used
to determine whether a secure system was in use or not.
This commit reworks the logic a little bit to avoid special casing
linux in main().
It also reworks the logic in CanReAuthenticate() to fix up some issues
"fixed" to correct converity warnings. The logic in this case was
mostly ok, but still didn't account for the proper usage of this
function. Error detection improved somewhat as a result.
In order for this to work, dtsession must be setuid root. If
dtsession is not setuid root, then locking will be disabled, and a
message will be written to ~/.dt/errorlog with the message: "Unable to
lock display due to security restrictions".
