Install clang on the windows environments #174
Description
I was trying to use cross for compiling to the x86_64-pc-windows-gnu target, however because one of my crates runs bindgen as part of a build.rs script, it fails.
$ cross build --target x86_64-pc-windows-gnu
...
error: failed to run custom build command for `litecad-sys v0.1.0 (file:///project/litecad-sys)`
process didn't exit successfully: `/target/debug/build/litecad-sys-a9c3850875a197e1/build-script-build` (exit code: 101)
--- stdout
rerun-if-changed=wrapper.h
rerun-if-changed=LiteCAD.h
--- stderr
thread 'main' panicked at 'Unable to find libclang: "couldn\'t find any of [\'libclang.so\', \'libclang.so.*\', \'libclang-*.so\'], set the LIBCLANG_PATH environment variable to a path where one of these files can be found (skipped: [])"', libcore/result.rs:916:5
note: Run with `RUST_BACKTRACE=1` for a backtrace.
Would it be a good idea for the underlying docker image windows builds run on to have clang installed?