FFI: Automatically generate bindings when building with ffi feature.

Cargo.toml

@@ -25,6 +25,9 @@ thiserror = "1"
 [dev-dependencies]
 env_logger = "0.8"
 
+[build-dependencies]
+cbindgen = "0.18.0"
+
 [target.'cfg(windows)'.dependencies]
 tolk = { version = "0.3", optional = true }
 windows = "0.2"

build.rs

@@ -8,4 +8,18 @@ fn main() {
             println!("cargo:rustc-link-lib=framework=AppKit");
         }
     }
+
+    #[cfg(feature = "ffi")]
+    generate_c_bindings();
+}
+
+#[cfg(feature = "ffi")]
+fn generate_c_bindings() {
+    use std::path::PathBuf;
+    let crate_dir = std::env::var("CARGO_MANIFEST_DIR").unwrap();
+    let mut header_path: PathBuf = std::env::var("OUT_DIR").unwrap().into();
+    header_path.push("tts.h");
+    cbindgen::generate(crate_dir)
+        .unwrap()
+        .write_to_file(header_path);
 }