Get `run_key_action` to export correctly to C

Add a new wrapper function for `run_key_action` that uses C appropriate
inputs & outputs and calls into our Rusty `run_key_action`. This new
function now correctly gets a header generated for it by 'cbindgen'.

Immense thanks to Jake Goulding on the Rust FFI Omnibus for showing me
how to pass a slice argument from C:
http://jakegoulding.com/rust-ffi-omnibus/slice_arguments/

In order to pass the slice from C, we need to pass a C array and its
length to the function. Cool.

1 files changed, 1 insertions, 0 deletions

diff --git a/Cargo.toml b/Cargo.toml
index dca6231..2c2176e 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -5,6 +5,7 @@ version = "0.0.1"
 [dependencies]
 cocoa = "0.18.0"
 combine = "3.4.0"
+libc = "0.2.43"
 
 [build-dependencies]
 cbindgen = "0.6.2"