[RFA] Submit process record and replay third time, 0/9

[teawater <teawater at gmail dot com>]

For this submit, I changed the names of some code and move the code in
linux-nat.c to record.c.
Thanks for help of everybody in the maillist.

Process record and replay make gdb can record inferior execute log and
replay (include reverse debug).
Now, it support I386-Linux single-thread inferior native debug.

I've divided this patch into ten sections, for ease of review.
They group as:
1) Architecture support layer (gdbarch.sh, gdbarch.c, gbarch.h).
2) New stratum of strata in target layer (target.h).
3) Process record and replay target (record.c, record.h, Makefile.in).
4) Set the variables for process record and replay target (target.c).
5) Process record and replay for Linux (linux-record.c,
linux-record.h, Makefile.in, configure.tgt).
6) Event handling (infrun.c).
7) Intel 386 target-dependent stuff (i386-tdep.c, i386-tdep.h).
8) Target-dependent code for GNU/Linux i386 (i386-linux-tdep.c).
9) User interface and documentation.

For the NEWS:
* Process record and replay

 In a architecture environment that supports ``process record and
 replay'', ``process record and replay'' target can record a log of
 the process execution, and replay it with both forward and reverse
 execute commands.

These patches be tested with testsuite gdb.twreverse in branch
reverse-20081226-branch.