Can't run scene from inside editor

[clayjohn]

Godot version:
Master
Reverting this commit 85cc435 fixes the issue

OS/device including version:
Ubuntu 16.04
Awesome WM

Issue description:
The editor opens fine, but when you click to launch the scene within editor it won't open another window and immediately exits with the following error:
drivers/unix/net_socket_posix.cpp:199 - Socket error - 104

And in the terminal the following printout

X Error of failed request:  BadAtom (invalid Atom parameter)
  Major opcode of failed request:  20 (X_GetProperty)
  Atom id in failed request:  0x0
  Serial number of failed request:  199
  Current serial number in output stream:  199

My guess is that this line is the culprit

godot/platform/x11/os_x11.cpp

Line 1192 in 48d3163

if (XGetWindowProperty(x11_display, x11_window, prop, 0, 4, False, AnyPropertyType, &type, &format, &len, &remaining, &data) == Success) {

Maybe "_NET_FRAME_EXTENTS" is not available on every device/version of x11?
edit: after doing more research this appears to be the case awesome WM doesn't support it and apparently many others don't as well.

@bruvzg Tagging you as you were the one to make the commit, any reason why this would cause the issue?

Steps to reproduce:

1. Compile from master
2. run
3. try to play scene from within editor

[akien-mga]

Related to #28538 (affecting i3wm and also caused by #26977) which was fixed by #28557.

[clayjohn]

To add more info. It seems that I can also fix this on my end by updating my WM. It may be the case that the majority of WMs wont have problems so long as they are up to date. In which case it may not be worth fixing.

@akien-mga What do you think?

[akien-mga]

It would probably be best to add some fallback code for WMs which don't support this (yet) to make sure it works fine.

[bruvzg]

Confirmed, XGetWindowProperty crashes if atom is invalid, "_NET_FRAME_EXTENTS" was added EWMH version 1.3 (in 2005), check #28784.