Mark all extensions as free-threading safe

This is not actually guaranteed to be true at the moment, but may be
useful for testing.

Author: QuLogic

src/_backend_agg_wrapper.cpp

@@ -185,7 +185,7 @@ PyRendererAgg_draw_gouraud_triangles(RendererAgg *self,
     self->draw_gouraud_triangles(gc, points, colors, trans);
 }
 
-PYBIND11_MODULE(_backend_agg, m)
+PYBIND11_MODULE(_backend_agg, m, py::mod_gil_not_used())
 {
     py::class_<RendererAgg>(m, "RendererAgg", py::buffer_protocol())
         .def(py::init<unsigned int, unsigned int, double>(),

src/_c_internal_utils.cpp

@@ -183,7 +183,7 @@ mpl_SetProcessDpiAwareness_max(void)
 #endif
 }
 
-PYBIND11_MODULE(_c_internal_utils, m)
+PYBIND11_MODULE(_c_internal_utils, m, py::mod_gil_not_used())
 {
     m.def(
         "display_is_valid", &mpl_display_is_valid,

src/_image_wrapper.cpp

@@ -200,7 +200,8 @@ image_resample(py::array input_array,
 }
 
 
-PYBIND11_MODULE(_image, m) {
+PYBIND11_MODULE(_image, m, py::mod_gil_not_used())
+{
     py::enum_<interpolation_e>(m, "_InterpolationType")
         .value("NEAREST", NEAREST)
         .value("BILINEAR", BILINEAR)

src/_path_wrapper.cpp

@@ -368,7 +368,7 @@ Py_is_sorted_and_has_non_nan(py::object obj)
     return result;
 }
 
-PYBIND11_MODULE(_path, m)
+PYBIND11_MODULE(_path, m, py::mod_gil_not_used())
 {
     m.def("point_in_path", &Py_point_in_path,
           "x"_a, "y"_a, "radius"_a, "path"_a, "trans"_a);

src/_qhull_wrapper.cpp

@@ -276,7 +276,8 @@ delaunay(const CoordArray& x, const CoordArray& y, int verbose)
     return delaunay_impl(npoints, x.data(), y.data(), verbose == 0);
 }
 
-PYBIND11_MODULE(_qhull, m) {
+PYBIND11_MODULE(_qhull, m, py::mod_gil_not_used())
+{
     m.doc() = "Computing Delaunay triangulations.\n";
 
     m.def("delaunay", &delaunay, "x"_a, "y"_a, "verbose"_a,

src/_tkagg.cpp

@@ -333,7 +333,7 @@ load_tkinter_funcs()
 }
 #endif // end not Windows
 
-PYBIND11_MODULE(_tkagg, m)
+PYBIND11_MODULE(_tkagg, m, py::mod_gil_not_used())
 {
     try {
         load_tkinter_funcs();

src/ft2font_wrapper.cpp

@@ -1594,7 +1594,7 @@ ft2font__getattr__(std::string name) {
         "module 'matplotlib.ft2font' has no attribute {!r}"_s.format(name));
 }
 
-PYBIND11_MODULE(ft2font, m)
+PYBIND11_MODULE(ft2font, m, py::mod_gil_not_used())
 {
     if (FT_Init_FreeType(&_ft2Library)) {  // initialize library
         throw std::runtime_error("Could not initialize the freetype2 library");

src/tri/_tri_wrapper.cpp

@@ -2,7 +2,8 @@
 
 using namespace pybind11::literals;
 
-PYBIND11_MODULE(_tri, m) {
+PYBIND11_MODULE(_tri, m, py::mod_gil_not_used())
+{
     py::class_<Triangulation>(m, "Triangulation", py::is_final())
         .def(py::init<const Triangulation::CoordinateArray&,
                       const Triangulation::CoordinateArray&,