Linux on gdb simulation

This target only testing.

Required software

gdb with I/O simulation enhance patch.
- Source code is here. It include h8300-unkown-linux changes.

examples below.

$ h8300-unknown-linux-gdb vmlinux
(gdb) target sim
(gdb) sim sci pty
(gdb) sim intmode 1
(gdb) load
(gdb) run earlyprintk=h8300-sim console=ttySC0

h8300-linux-toolchain ()	2015-04-29 15:05
kernel (kernel binary (NFS Root))	2002-08-24 15:01
kernel-2.4 (uClinux-2.4.26-uc0_patch)	2004-05-11 00:47
kgdb-patch (2.4.x)	2005-02-15 17:09
libc (uClibc-0.9.27)	2005-03-14 23:08
linux-2.5.x-h8300 patches (linux-2.5.72)	2003-06-19 01:28
linux-2.6 patches (linux-2.6.7)	2004-06-17 21:48
ToolChain SRPMS/SPECS (gcc nosrc)	2002-07-31 21:33
u-boot (20110303)	2011-03-03 22:03
uClinux-dist (module-support)	2004-05-18 18:49
Utilities (dumpromfs)	2005-03-24 16:49