This patch is the bulk of the new WinCE support.
It contains:

      - The new WinCE support on gdb/ side.
      - The gdbserver port.

WinCE has the following (and a few more) twists:
          - No errno/perror/strerror - The runtime only knows about
            GetLastError/SetLastError.
          - No signals support.
          - The initial breakpoint (the automatically inserted
            at the entry point breakpoint) must be inserted manually.
          - All programs link to coredll.dll instead of kernel32.dll.
          - CreateProcess has the same signature as the 9x/NT Windows,
            but a bunch of parameters are unsupported, and the
            image name (first param) must never be null.

There was a little bug in win32-low.c
(original win32-i386-low.c).  There was a call to
strerror (GetLastError ()), but strerror should take an errno
value, not a winerror, as the error codes are not compatible.
That was fixed by using a new strwinerror function, that is
used also as a replacement for strerror on WinCE.

The patch moves the gdbserver i386 specifics into a new
win32-i386-low.c, and the new arm stuff into
win32-arm-low.c.  The changes were modelled on the linux
support.  It was done this way to minimize the #ifdefery.

The arm/i386 differences are mostly:
     - the gdb/'win32 Context' register mappings
     - I need to store the ARM WinCE breakpoint opcode somewhere - it
       is used to insert the initial breakpoint.
     - The i386 debug registers handling (although watchpoint support isn't
       really implemented in win32-i386-low.c currently; gdb/i386-nat.c
       would have to be copied/used from gdbserver).

Note that i386/arm is orthogonal to 9x/NT/CE.  WinCE can also be i386.

I stashed the i386 debug registers copying into a
load/store interface, mainly because I needed to get them out
of the generic win32-low.c.  I'm open to better suggestions.
Note that although the debug registers handling code was copied from
gdb/win32-nat.c, watchpoints are not supported, making the
debug registers copying unneeded; they could be disabled until
proper watchpoint support is implemented.

With this patch, the old config/arm/tm-wince.h, wince.c,
wince-stub.h and wince-stub.c file can finally go away.

Cheers,
Pedro Alves