Fixed Windows jsglue Builds with Define for Built-in offsetof (#550)

Signed-off-by: Redfire <[email protected]>

Author: redfire75369

mozjs-sys/build.rs

@@ -781,7 +781,12 @@ mod jsglue {
             .clang_args(["-include", &confdefs_path.to_str().expect("UTF-8")]);
 
         if msvc {
-            builder = builder.clang_args(["-fms-compatibility", "-DWIN32", "-std=c++17"])
+            builder = builder.clang_args([
+                "-fms-compatibility",
+                "-DWIN32",
+                "-D_CRT_USE_BUILTIN_OFFSETOF",
+                "-std=c++17",
+            ])
         } else {
             builder = builder.clang_args(["-fPIC", "-fno-rtti", "-std=c++17"])
         }