config: Add a function to read a config file (WIP)

A new function that will read a TOML config file. Doesn't currently
access the filesystem. This commit is mostly supporting code to allow
that to work.

* Add the 'toml' crate
* `parse_args()`: Take a mutable `Config` and return that config instead
  of creating a new one. The recipe will now be to read the config from
  a file first and then pass that config to this function to be updated.
* Modify `c_parse_args()` to take a `*Config` and mirror the new method
  signature of `parse_args()`

1 files changed, 1 insertions, 1 deletions

diff --git a/dome_key_map.h b/dome_key_map.h
index 2a73d8f..224cc21 100644
--- a/dome_key_map.h
+++ b/dome_key_map.h
@@ -36,7 +36,7 @@ typedef struct {
   size_t length;
 } Trigger;
 
-Config *c_parse_args(const char *const *args, size_t length);
+Config *c_parse_args(const char *const *args, size_t length, Config *config_ptr);
 
 void c_run_key_action(State *state, Trigger trigger, const Trigger *mode);