Removes ion-c-sys (#457)

.gitmodules

@@ -1,9 +1,6 @@
 [submodule "ion-tests"]
 	path = ion-tests
 	url = https://github.com/amzn/ion-tests.git
-[submodule "ionc"]
-	path = ion-c-sys/ion-c
-	url = https://github.com/amzn/ion-c.git
 [submodule "ion-hash-test"]
 	path = ion-hash/ion-hash-test
 	url = https://github.com/amzn/ion-hash-test.git

Cargo.toml

@@ -24,8 +24,6 @@ rust-version = "1.65"
 
 [workspace]
 members = [
-  "ion-c-sys",
-  "ion-c-sys-macros",
   "ion-hash"
 ]
 

README.md

@@ -12,7 +12,7 @@ A Rust implementation of the [Amazon Ion][spec] data format.
 
 ## Development
 
-This project uses a submodule to pull in [Ion C][ion-c] and [Ion Tests][ion-tests].  The easiest way to pull
+This project uses a submodule to pull in [Ion Tests][ion-tests].  The easiest way to pull
 everything in is to clone the repository recursively:
 
 ```bash
@@ -25,22 +25,18 @@ You can also initialize the submodules as follows:
 $ git submodule update --init --recursive
 ```
 
-Furthermore, you will need the [pre-requisties for `bindgen`][bindgen-req] installed which is basically
-`libclang`.
-
 Building the project:
 
 ```bash
 $ cargo build --workspace --all-targets
 ```
 
-Running all tests for `ion-rust` and `ion-c-sys`:
+Running all tests for `ion-rust`:
 
 ```bash
 $ cargo test --workspace
 ```
 
 [spec]: https://amzn.github.io/ion-docs/docs/spec.html
-[ion-c]: https://github.com/amzn/ion-c
 [ion-tests]: https://github.com/amzn/ion-tests
 [bindgen-req]: https://rust-lang.github.io/rust-bindgen/requirements.html