Check if 'GLX_ARB_get_proc_address' is supported before using

dlls/opengl32/wgl.c

@@ -624,6 +624,7 @@ static BOOL process_attach(void)
   Window root = (Window)GetPropA( GetDesktopWindow(), "__wine_x11_whole_window" );
   HMODULE mod = GetModuleHandleA( "x11drv.dll" );
   void *opengl_handle;
+  const char *extensions = NULL;
   
   if (!root || !mod)
   {
@@ -665,14 +666,17 @@ static BOOL process_attach(void)
   vis = XGetVisualInfo(default_display, VisualIDMask, &template, &num);
   if (vis != NULL) default_cx = glXCreateContext(default_display, vis, 0, GL_TRUE);
   if (default_cx != NULL) glXMakeCurrent(default_display, root, default_cx);
+  extensions = glXQueryExtensionsString(default_display, DefaultScreen(default_display));
   XFree(vis);
   LEAVE_GL();
 
+  if ((extensions != NULL) && (strstr(extensions, "GLX_ARB_get_proc_address"))) {
     opengl_handle = wine_dlopen(SONAME_LIBGL, RTLD_NOW|RTLD_GLOBAL, NULL, 0);
     if (opengl_handle != NULL) {
       p_glXGetProcAddressARB = wine_dlsym(opengl_handle, "glXGetProcAddressARB", NULL, 0);
       wine_dlclose(opengl_handle, NULL, 0);
     }
+  }
   
   if (default_cx == NULL) {
     ERR("Could not create default context.\n");