Expose the crate's manifest dir to dependent crates

build.rs

@@ -0,0 +1,21 @@
+/*
+ * Copyright (c) godot-rust; Bromeon and contributors.
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+/// Build script to expose the crate's manifest directory to dependent crates.
+///
+/// This allows dependent crates to locate platform-specific prebuilt bindings
+/// during cross-compilation, where cfg attributes are evaluated for the host
+/// platform instead of the target platform.
+///
+/// Dependent crates can access this via the `DEP_GDEXTENSION_API_ROOT` environment variable.
+fn main() {
+    // Export the manifest directory so dependent crates can find our files
+    let manifest_dir =
+        std::env::var("CARGO_MANIFEST_DIR").expect("CARGO_MANIFEST_DIR should be set by Cargo");
+
+    println!("cargo:root={}", manifest_dir);
+}

src/lib.rs

@@ -23,19 +23,19 @@ pub const GODOT_VERSION_STRING: &str = "4.5";
 
 /// Returns the contents of the header file `gdextension_interface.h`.
 pub const fn load_gdextension_header_h() -> CowStr {
-    CowStr::Borrowed(include_str!("../../4.5/res/gdextension_interface.h"))
+    CowStr::Borrowed(include_str!("../res/gdextension_interface.h"))
 }
 
 /// Returns the contents of the header file `gdextension_interface.rs`, generated for the corresponding platform.
 pub const fn load_gdextension_header_rs() -> CowStr {
     #[cfg(windows)]
-    let s = include_str!("../../4.5/res/gdextension_interface_windows.rs");
+    let s = include_str!("../res/gdextension_interface_windows.rs");
 
     #[cfg(target_os = "macos")]
-    let s = include_str!("../../4.5/res/gdextension_interface_macos.rs");
+    let s = include_str!("../res/gdextension_interface_macos.rs");
 
     #[cfg(all(unix, not(target_os = "macos")))]
-    let s = include_str!("../../4.5/res/gdextension_interface_linux.rs");
+    let s = include_str!("../res/gdextension_interface_linux.rs");
 
     CowStr::Borrowed(s)
 }