Yet another magic symlinks implementation

[Matthew Dillon]

    It is interesting to note that DragonFly has had variant symlnks for 
    a long time, but we haven't actually found a use for them yet.   No
    smoking killer app has presented itself.  We use varsyms in our RC
    implementation kind of like uber-environment variables (rclist, rcstart,
    rcstop, etc), but we don't actually use them in symlinks.

    Originally I envisioned using variant symlinks as part of a packaging
    system to allow package environments to be built on the fly, thus
    allowing multiple versions of libraries to coreside and not have the
    'you have to upgrade everything to install one new thing' problem.
    But that was before we adopted pkgsrc.  Pkgsrc doesn't use varsyms,
    so...

    The concept is interesting enough that I'm not going to rip it out.

						-Matt