Remove compat_osf1, discussed on tech-kern@.

Remove reference to compat_darwin (was retired a long time ago).

Retire compat_ibcs2, as discussed on tech-kern@. FreeBSD did the same
recently.

Remove compat_svr4 and compat_svr4_32, as discussed on tech-kern@ recently,
but also as discussed several times in the past.

branches: 1.25.10; 1.25.12;
Use serial comma. Update a count.

Add some more text from FreeBSD.

branches: 1.23.8;
whitespace.

Clarify the behavior of the @machine and @machine_arch magic links
relative to uname output when running in emulations: the magic links
are *not* affected even though uname output changes.

(This means @machine magic links can be used for e.g. amd64 vs. i386
device nodes. There's also an @emul magic link for emulation.)

Noted by apb.

branches: 1.21.2; 1.21.8;
Use .Ss and -offset indent.

branches: 1.20.2;
Remove PECOFF/Win32 emulation.

prettier markup

merge the two lists.

branches: 1.17.2;
document gid, rgid

Fix markup

branches: 1.15.2;
Bump date for mjf's Dec 4 2007 commit that corrected the description of
magiclinks and added @ruid.

branches: 1.14.2;
Fix spelling typo.

branches: 1.13.6; 1.13.10;
Implement a new magic string for magic symlinks, @ruid, which exapnds to the
real user id of the process and use this magic string for per-user tmp.
This should fix PR/35687

Kernel parts reviewed by wrstuden@

branches: 1.12.4;
Bump date for previous.

Added a HISTORY section.

branches: 1.10.2;
Add "@uid" keyword translation, to translate effective user-id of the
process.

Document the new @emul magic symlink var as well as the new @{var} syntax.

Bump date for new magic symlinks, and add uname(1) to SEE ALSO.

Implement expansion of special "magic" strings in symlinks into
system-specific values. Submitted by Chris Demetriou in Nov 1995 (!)
in PR kern/1781, modified only slighly by me.

This is enabled on a per-mount basis with the MNT_MAGICLINKS mount
flag. It can be enabled at mountroot() time by building the kernel
with the ROOTFS_MAGICLINKS option.

The following magic strings are supported by the implementation:

@machine value of MACHINE for the system
@machine_arch value of MACHINE_ARCH for the system
@hostname the system host name, as set with sethostname()
@domainname the system domain name, as set with setdomainname()
@kernel_ident the kernel config file name
@osrelease the releaes number of the OS
@ostype the name of the OS (always "NetBSD" for NetBSD)

Example usage:

mkdir /arch/i386/bin
mkdir /arch/sparc/bin
ln -s /arch/@machine_arch/bin /bin

branches: 1.6.6;
Move UCB-licensed code from 4-clause to 3-clause licence.

Patches provided by Joel Baker in PR 22309, verified by myself.

Add lchflags() to the list of syscalls that act on symlinks.

Make DESCRIPTION sections (mostly by renaming non-standard section headers).
[See bin/14591 for a reason why we should have them.]

Punctuation fixes.

Boring whitespace fixes.

branches: 1.1.4;
Move symlink.7 to share/man/man7/, where it belongs