Avoid calling XOpenDisplay multiple times, fixes crashes on Intel Mesa

* See https://bugs.freedesktop.org/show_bug.cgi?id=99831
  https://bugs.freedesktop.org/show_bug.cgi?id=54971
* It's not clear if it's invalid to call XOpenDisplay more than once but
  at the very least it's only really used as convenience to avoid
  plumbing the display handle through.

qrenderdoc/Code/qrenderdoc.cpp

@@ -182,6 +182,15 @@ int main(int argc, char *argv[])
     GUIInvoke::init();
 
     PythonContext::GlobalInit();
+
+    {
+      GlobalEnvironment env;
+#if defined(RENDERDOC_PLATFORM_LINUX)
+      env.xlibDisplay = QX11Info::display();
+#endif
+      RENDERDOC_InitGlobalEnv(env, rdctype::array<rdctype::str>());
+    }
+
     {
       CaptureContext ctx(filename, remoteHost, remoteIdent, temp, config);