Mark json with Py_MOD_GIL_NOT_USED & remove PYTHON_GIL env var from ci test job

Author: lysnikolaou

.github/workflows/unit-tests.yml

@@ -388,8 +388,6 @@ jobs:
 
       - name: Run Tests
         uses: ./.github/actions/run-tests
-        env:
-          PYTHON_GIL: 0
 
   # NOTE: this job must be kept in sync with the Pyodide build job in wheels.yml
   emscripten:

pandas/_libs/src/vendored/ujson/python/ujson.c

@@ -384,6 +384,10 @@ PyMODINIT_FUNC PyInit_json(void) {
     return NULL;
   }
 
+#ifdef Py_GIL_DISABLED
+  PyUnstable_Module_SetGIL(module, Py_MOD_GIL_NOT_USED);
+#endif
+
 #ifndef PYPY_VERSION
   PyObject *mod_decimal = PyImport_ImportModule("decimal");
   if (mod_decimal) {