Enable link-time optimization when building Rust library for production

This decreases the compiled library size and improves performance.

codegen-units is also set to 1 to further optimize the compiled library.

Author: Calinou

docker/Dockerfile

@@ -20,6 +20,8 @@ RUN apt-get update && DEBIAN_FRONTEND=noninteractive apt-get install -y \
 # Update PATH for cargo
 ENV RUSTUP_HOME=/usr/local/rustup \
     CARGO_HOME=/usr/local/cargo \
+    RUSTFLAGS="-C codegen-units=1" \
+    CARGO_PROFILE_RELEASE_LTO=fat \
     PATH=/usr/local/cargo/bin:$PATH
 
 # Install Rust toolchain, see https://rust-lang.github.io/rustup/installation/other.html

publish_windows.py

@@ -24,6 +24,13 @@
 pathlib.Path(dst_dir).mkdir(parents=True, exist_ok=True)
 pathlib.Path(dst_dir_debug).mkdir(parents=True, exist_ok=True)
 
+# Build GDNative library with production optimizations
+subprocess.run(
+    ["cargo", "build", "--release"],
+    cwd="rust",
+    env={"RUSTFLAGS": "-C codegen-units=1", "CARGO_PROFILE_RELEASE_LTO": "fat"}
+)
+
 # Copy all dlls
 src_dir = "godot"
 for dll in glob.iglob(os.path.join(src_dir, "*.dll")):