Changes for supporting native Windows compilation

[Martin Grabmueller]

Hello list,

the maintainer (Stefan Jahn, address@hidden) of GNU Serveez
(http://www.gnu.org/software/serveez) recently asked me if the Guile
maintainers would accept patches to make Guile compile under native
Windows, using the M$ Visual C compiler.  He already made a native
port of guile-1.4 (excluding the posix functions), and would like to
see the patches go into the distribution.  Below is a list of what he
had to change:

> Hereby I send you the requested overview:

>  * do not change readline's in- and output stream
>  * choose native Win32 api for waiting for input events instead of select()
>  * define something like GUILE_API to identify exported functions
>  * maybe use __int64 instead of long long
>  * replace ftruncate() and truncate() by chsize()
>  * access checking for file descriptors has to be changed (fcntl)
>  * startup and cleanup Winsock API
>  * use Winsock API instead of standard unix networking (different headers)
>  * check signal names and drop the use of alarm()
>  * use raise() instead of kill (getpid ())
>  * change libtool's build process for DLLs

With these changes a

./configure --disable-posix --enable-regex --disable-debug-malloc \
            --disable-debug-freelist --with-modules --enable-guile-debug \
            --without-threads --enable-ltdl-convenience \
            --cache-file=config.cache --prefix=/mingw
make

does result in a working Guile.

And yes, we know that a cygwin port does exist and is functional, but
it is too slow for the requirements of GNU Serveez.

Thanks,
  'martin