fix xwin cross-compilation

README.md

@@ -68,3 +68,11 @@ on Windows when using Microsoft Visual C++ (MSVC).
 
 MicroSEH is compatible with and has been tested on Windows platforms with the following
 architectures: **x86**, **x86_64** and **aarch64**.
+
+When building for other unsupported platforms, the library will disable exception
+handling and panic when `try_seh` is called.
+
+## Cross-Compiling
+
+Cross-compiling for Windows is possible with full support for SEH using the
+[cargo-xwin](https://github.com/rust-cross/cargo-xwin) project.

build.rs

@@ -1,16 +1,12 @@
-#[cfg(all(windows, not(docsrs)))]
-extern crate cc;
-
-#[cfg(all(windows, not(docsrs)))]
 fn main() {
-    // TODO: this is a hack to allow this crate to build on docs.rs.
+    // NOTE: this is a hack to allow this crate to build on docs.rs.
     //       https://github.com/sonodima/microseh/pull/11#issuecomment-2385633164
-    if !std::env::var("HOST").unwrap_or_default().contains("gnu") {
-        cc::Build::new().file("src/stub.c").compile("sehstub");
+    if std::env::var_os("CARGO_CFG_DOCSRS").is_some()
+        || std::env::var_os("CARGO_CFG_WINDOWS").is_none()
+    {
+        println!("cargo:warning=building for a non-supported platform, exception handling will not be available");
+        return;
     }
-}
 
-#[cfg(any(not(windows), docsrs))]
-fn main() {
-    println!("cargo:warning=building for a non-supported platform, exception handling will not be available");
+    cc::Build::new().file("src/stub.c").compile("sehstub");
 }