Pull in <time.h> for struct tm, used in rcs.h

ok deraadt@

Convert xfree to free. From Fritjof Bornebusch. ok deraadt

An internal function called xrealloc() is actually a fail-hard
reallocarray()... so rename it.

not compiled before commit

Fixed uninitialized pointer (and other struct entries while at it)
which is referenced while parsing invalid RCS files.

Spotted by jsg.

ok deraadt

Convert the logic in rcsparse_warnx(). Instead of creating a
temporary format string, create a temporary message.
If there is not enough memory to log the error, just log this second
error. The double error path gets never tested, so it should be
simple. Make it work like the other places.
OK doug@

Zap some stored values never read; From Fritjof Bornebusch; ok nicm@

properly handle commitid tokens found in rcs files

ok deraadt

Sync rcsparse between OpenCVS/OpenRCS. Spaces, no binary change.

spacing, no binary change.

Fix a typo in a comment, from Michael W Bombardieri.

- remove unused variables

from Michael W. Bombardieri
ok chl@ nicm@

Remove the need for rp_file in parser structure, instead keep only one
FILE pointer in RCSFILE. This fixes some ugliness in closing an
fdopen()ed FILE and its underlying file descriptor.

Notified by Joerg Sonnenberger <joerg at britannica dot bec to de>

discussed with and ok nicm

Prevent a NULL pointer dereference if rcsparse_deltatexts is called with
a revision not specified as delta in an RCS file.

Spotted by and ok zinovik

No need to remove RCS_PARSE flag from rf_flags after successfully parsing.

Replaced RCS parser code with new rcsparse.{c,h}:
- be very strict about things we parse
- print more information about errors if they occur
- do not fatal() directly in parser, give caller a chance to react
- fix an rcs design issue when it comes to login names

tested by many on tech@

ok xsa