feat: reorg code, and prepare for c bindings

deltachat-ffi/build.rs

@@ -0,0 +1,23 @@
+fn main() {
+    let crate_dir = std::env::var("CARGO_MANIFEST_DIR").unwrap();
+
+    let cfg = cbindgen::Config::from_root_or_default(std::path::Path::new(&crate_dir));
+
+    let c = cbindgen::Builder::new()
+        .with_config(cfg)
+        .with_crate(crate_dir)
+        .with_language(cbindgen::Language::C)
+        .generate();
+
+    // This is needed to ensure we don't panic if there are errors in the crates code
+    // but rather just tell the rest of the system we can't proceed.
+    match c {
+        Ok(res) => {
+            res.write_to_file("deltachat.h");
+        }
+        Err(err) => {
+            eprintln!("unable to generate bindings: {:#?}", err);
+            std::process::exit(1);
+        }
+    }
+}