Windows native support (with Microsoft Visual Studio)

[SamuelMarks]

> cmake -G "Visual Studio 18 2026" -DCMAKE_TOOLCHAIN_FILE="..\vcpkg\scripts\buildsystems\vcpkg.cmake" -A x64 -S . -B build
-- Selecting Windows SDK version 10.0.26100.0 to target Windows 10.0.26200.
-- The C compiler identification is MSVC 19.50.35730.0
[… omitted for brevity]
> cmake --build build --config Debug --parallel
[… omitted for brevity]

Which will produce a neat 2MB rsync.exe. Release mode gives a 440KB rsync.exe.

[tridge]

thanks!
Please add a CI job as well to test this, preferably with it running the test suite