[render_gl] Suppress Xlib errors

As of Bazel 9, we receive warings from Xlib header files, so we need
to suppress them.

Author: jwnimmer-tri

geometry/render_gl/internal_opengl_context.cc

@@ -108,7 +108,10 @@ class OpenGlContext::Impl {
                                   True,
                                   None};
     int fb_count = 0;
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wold-style-cast"
     const int screen_id = DefaultScreen(display());
+#pragma GCC diagnostic pop
 
     // No matter what, we want to make sure that the context is not current
     // at the conclusion of construction.
@@ -149,8 +152,11 @@ class OpenGlContext::Impl {
     bool is_complete = false;
 
     // This requires a call to XFreeColormap in the destructor.
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wold-style-cast"
     window_attribs.colormap = vtkXCreateColormap(
         display(), RootWindow(display(), screen_id), visual->visual, AllocNone);
+#pragma GCC diagnostic pop
     ScopeExit colormap_guard(
         [colormap = window_attribs.colormap, &is_complete]() {
           if (!is_complete) vtkXFreeColormap(display(), colormap);
@@ -160,10 +166,13 @@ class OpenGlContext::Impl {
     // redrawn.
     window_attribs.event_mask = ExposureMask;
     // This requires a call to XDestroyWindow in the destructor.
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wold-style-cast"
     window_ = vtkXCreateWindow(display(), RootWindow(display(), screen_id), 0,
                                0, window_width_, window_height_, 0,
                                visual->depth, InputOutput, visual->visual,
                                CWColormap | CWEventMask, &window_attribs);
+#pragma GCC diagnostic pop
     ScopeExit window_guard([window = window_, &is_complete]() {
       if (!is_complete) vtkXDestroyWindow(display(), window);
     });