Have tests targetting Linux by default on Windows

Author: upsuper

tests/tests.rs

@@ -137,6 +137,20 @@ fn create_bindgen_builder(header: &PathBuf) -> Result<Option<Builder>, Error> {
         }
     }
 
+    // Windows platform has various different conventions than *nix platforms,
+    // e.g. default enum underlying type, struct padding, mangling. Most tests
+    // were written and checked on Linux and macOS, and thus they could fail on
+    // Windows. We just make those tests targetting Linux instead as far as one
+    // isn't annotated for a specific target.
+    if cfg!(target_os = "windows") {
+        if flags.iter().all(|flag| !flag.starts_with("--target=")) {
+            if !flags.iter().any(|flag| flag == "--") {
+                flags.push("--".into());
+            }
+            flags.push("--target=x86_64-unknown-linux".into());
+        }
+    }
+
     // Fool builder_from_flags() into believing it has real env::args_os...
     // - add "bindgen" as executable name 0th element
     // - add header filename as 1st element