Merge branch 'ps/ci-rust'

CI improvements to handle the recent Rust integration better.

* ps/ci-rust:
  rust: support for Windows
  ci: verify minimum supported Rust version
  ci: check for common Rust mistakes via Clippy
  rust/varint: add safety comments
  ci: check formatting of our Rust code
  ci: deduplicate calls to `apt-get update`

meson.build

@@ -1708,6 +1708,10 @@ rust_option = get_option('rust').disable_auto_if(not cargo.found())
 if rust_option.allowed()
   subdir('src')
   libgit_c_args += '-DWITH_RUST'
+
+  if host_machine.system() == 'windows'
+    libgit_dependencies += compiler.find_library('userenv')
+  endif
 else
   libgit_sources += [
     'varint.c',