[bindings] Use global context for secp256k1

Note that this uses rust-bitcoin/rust-secp256k1#279

Author: TheBlueMatt

c-bindings-gen/src/types.rs

@@ -587,7 +587,7 @@ impl<'a, 'c: 'a> TypeResolver<'a, 'c> {
 	/// Returns true we if can just skip passing this to C entirely
 	fn no_arg_path_to_rust(&self, full_path: &str) -> &str {
 		if full_path == "bitcoin::secp256k1::Secp256k1" {
-			"&bitcoin::secp256k1::Secp256k1::new()"
+			"secp256k1::SECP256K1"
 		} else { unimplemented!(); }
 	}
 

lightning-c-bindings/Cargo.toml

@@ -16,8 +16,13 @@ crate-type = ["staticlib"
 
 [dependencies]
 bitcoin = "0.26"
+secp256k1 = { version = "0.20.1", features = ["global-context-less-secure"] }
 lightning = { version = "0.0.12", path = "../lightning" }
 
+[patch.crates-io]
+# Rust-Secp256k1 PR 279. Should be dropped once merged.
+secp256k1 = { git = 'https://github.com/TheBlueMatt/rust-secp256k1', rev = '15a0d4195a20355f6b1e8f54c84eba56abc15cbd' }
+
 # We eventually want to join the root workspace, but for now, the bindings generation is
 # a bit brittle and we don't want to hold up other developers from making changes just
 # because they break the bindings