Link library with a test C program

Make a test `includer.c` program that includes the Rust library and
calls our `c_run_key_action()` to see if it actually works. Currently it
doesn't, we get `(null)` printed to stdout.

Add a Makefile with the build command for the C program.

cbindgen.toml:
Remove `KeyActionResult` from exported types, as the `Option` field it
contains caused `gcc` to complain.

cocoa_bridge.rs:
* Comment out all 'cocoa' crate related code as the 'cocoa' code was
  interfering with GCC compilation as a result of my not linking to
  Cocoa frameworks.
* Add a new test map definition that corresponds with the one we look
  for in `includer.c`.

parser.rs:
Add `#[repr(C)]` to `MapKind` because it needs to be exported in the
library and generated into our C header file.

1 files changed, 4 insertions, 8 deletions

diff --git a/dome_key_map.h b/dome_key_map.h
index 1206d1d..647c6e5 100644
--- a/dome_key_map.h
+++ b/dome_key_map.h
@@ -12,18 +12,14 @@ typedef enum {
   Down,
 } HeadphoneButton;
 
-typedef struct MapKind MapKind;
-
-typedef struct Option_CString Option_CString;
+typedef enum {
+  Map,
+  Command,
+} MapKind;
 
 typedef struct {
   const char *action;
   const MapKind *kind;
 } CKeyActionResult;
 
-typedef struct {
-  Option_CString action;
-  MapKind kind;
-} KeyActionResult;
-
 const CKeyActionResult *c_run_key_action(const HeadphoneButton *trigger, size_t length);