Windows: Simplify compiling versioninfo.rc by using libtool facilities

Windows: Simplify compiling versioninfo.rc by using libtool facilities

libtool has built-in support for Windows resources, and we even
enable it in configure.ac. What it doesn't have is a built-in rule
for generating Libtool objects using that built-in support, but
we can add one.

We have to generate Libtool pseudo-objects (.lo) rather than native
object files (.o) so that we get both a PIC object for the shared
library and a non-PIC object for the static library.

This mimics the libtool invocations used for compiling C and C++.
Note that $(RC) is typically i686-w64-mingw32-windres, the same as
our project-specific variable $(WINDRES) which was previously used here.

Signed-off-by: Simon McVittie <smcv@collabora.com>
Bug: https://bugs.freedesktop.org/show_bug.cgi?id=103015
Reviewed-by: Philip Withnall <withnall@endlessm.com>
Reviewed-by: Ralf Habacker <ralf.habacker@freenet.de>