fix: Disable 64bit GC

build.rs

@@ -90,6 +90,12 @@ fn build_gcc(src_dir: &str) {
     buildcmd.stderr(Stdio::inherit());
     buildcmd.arg("--no-silent");
 
+    // This became enabled by default in https://github.com/LuaJIT/LuaJIT/commit/bd00094c3b50e193fb32aad79b7ea8ea6b78ed25
+    // but changes the generated bytecode. Bitsquid does not have it currently.
+    // The documentation changes in the commit mention that the bytecode change might be "rectified"
+    // in the future, though.
+    buildcmd.arg("XCFLAGS=-DLUAJIT_DISABLE_GC64");
+
     // We do need to cross-compile even here, so that `lj_vm.o` is created
     // for the correct architecture.
     if env::var("CARGO_CFG_WINDOWS").is_ok() {