* arbiters.c, eq.c, gc.c, guardians.c, list.c, ports.c, print.c,

* arbiters.c, eq.c, gc.c, guardians.c, list.c, ports.c, print.c,
regex-posix.c, scmsigs.c, stime.c, strings.c, variable.c, stime.c,
strings.c, variable.c:  Added lots of documentation, cleaned up
some existing documentation.  Occasionally changed formal params
to match docs.  Also folded an #ifdef into the inners of a
primitive instead of having two copies of the primitive
(`get-internal-real-time', from stime.c)