Add a check for 32bit Windows to target nightly Rust.

Previously, compiling with non-nightly Rust meant 32bit Windows would fail to generate bindings - bindgen will not use the "thiscall" ABI unless using nightly Rust. The bindings would therefore have (almost) nothing in them, so any calls would fail. Now at least there will be a warning, and if using nightly Rust, this will work!

Author: andriyDev

build.rs

@@ -45,6 +45,18 @@ fn is_debug() -> bool {
   env::var("DEBUG").unwrap() == "true"
 }
 
+fn is_32_bit() -> bool {
+  env::var("TARGET")
+    .expect("TARGET should be provided by Cargo.")
+    .contains("i686")
+}
+
+fn is_nightly() -> bool {
+  env::var("RUSTUP_TOOLCHAIN")
+    .expect("RUSTUP_TOOLCHAIN should be provided by Cargo.")
+    .starts_with("nightly")
+}
+
 fn lib_names() -> Vec<String> {
   let mut root_names = Vec::new();
   #[cfg(feature = "recast")]
@@ -175,7 +187,7 @@ fn generate_recast_bindings(
     add_to_builder: impl Fn(bindgen::Builder) -> bindgen::Builder,
     out_file: PathBuf,
   ) {
-    let builder = bindgen::Builder::default()
+    let mut builder = bindgen::Builder::default()
       .parse_callbacks(Box::new(bindgen::CargoCallbacks))
       .clang_args(["-x", "c++"].iter())
       .clang_args(
@@ -190,8 +202,18 @@ fn generate_recast_bindings(
       .blocklist_file(".*stddef\\.h")
       .blocklist_type("max_align_t");
 
+    if is_windows() && is_32_bit() {
+      if is_nightly() {
+        builder = builder.rust_target(bindgen::RustTarget::Nightly);
+      } else {
+        println!("cargo:warning=Windows 32 bit uses the \"thiscall\" ABI. This feature is not enabled, so compilation may fail!");
+      }
+    }
+
     #[cfg(feature = "detour_large_nav_meshes")]
-    let builder = builder.clang_args(["-DDT_POLYREF64"]);
+    {
+      builder = builder.clang_args(["-DDT_POLYREF64"]);
+    }
 
     let bindings =
       add_to_builder(builder).generate().expect("Unable to generate bindings.");