The initial MSVC 201x projects inadvertly disabled
RandomizedBaseAddress, which is normally enabled by default, so ensure
that is the case for all 201x builds. This feature is supported by
Visual Studio 2010 or later.
Also, for x64 builds on MSVC 2012 or later, use /HIGHENTROPYVA when
linking.
Pointed out by Ignacio Casal Quinteiro.
The latest upstream libffi is getting bit-rotten with the Windows/MSVC
builds, and since we are eventually moving to a Meson-based build system,
make use of the Centricular fork of libffi[1], which is better maintained
and tested for builds on Windows, with the use of DLLs over static libraries
and elimination of awkward build flags that we had to use for GObject.
[1]: https://github.com/centricular/libffi
Use the new gen_util_scripts.py script to generate the glib-mkenums and
gdbus-codegen scripts with the proper info in them so that they can be
used properly by other build systems such as Meson, during "install".
It was suggested that the project files be moved here as we don't actually
need to go two directory layers from $(srcroot), and would help us to
standardize on things in the future across the board.
