Wrap some MSVC options in the compile script.

Wrap some MSVC options in the compile script.

* lib/compile: MSVC supports naming the output file, the option
is just not called -o, so transform -o into the appropriate form
for MSVC. Also wrap some other options while at it (-L, -l, -Wl,
-Xlinker and -I) and convert file names to windows form where
needed for those options to make MSVC more usable in an
autotooled environment.
* doc/automake.texi (Auxiliary Programs): Document the above
extension of the compile script.
* NEWS: Updated.
* tests/defs.in: New required entry 'cl'.
* tests/compile3.test: New test.
* tests/compile4.test: New test.
* tests/compile5.test: New test.
* tests/Makefile.am: Update.

Signed-off-by: Ralf Wildenhues <Ralf.Wildenhues@gmx.de>