MSVC: Add MSVC support.

[Peter Rosin]

Hi!

This is basically
"Add MSVC support."
9c848f1e8acdf435d019aa80f3f0b0aeb45613f7

but with some things removed, which makes it depend on
the proposed changes to the compile script in automake.

This patch should be a NOP unless you are using the
Microsoft C/C++ Compiler (aka MSVC, aka cl) and are
on a windows $host.

Since it changes the indentation of some other code
I'm attaching a diff -b (msvc-b.diff) as well as the
exported change from git (msvc.patch).

There are many failures in the testsuite with MSVC
with this patch, at least for MSVC 2005 which is the
compiler I'm using by default, due to problems with
manifests. See below. So I'm not publishing any
testsuite results this time, they are too just
disappointing. Please hold.

For this patch I'm looking for an ok to commit, but
I'm going to hold the actual commit until I have done
a couple of more things:

* I have a similar ok for one more patch (.manifest
  related, 9f550cb81d4dfe4fc8962f23a7eccb1152e5c4a5)
* I have run the testsuite on Cygwin, MinGW/gcc and
  MinGW/msvc and verified that there are no regressions.
* maybe (if you think I should) wait for the proposed
  compile script to be commited to automake.

Cheers,
Peter

msvc.patch
Description: Source code patch

msvc-b.diff
Description: Text document