Fix crash with eglGetDisplay(EGL_DEFAULT_DISPLAY) on linux

* We'll try to get a default display when xlib is available, otherwise there's
  nothing we can do and keyboard input will not be available.

renderdoc/driver/gl/egl_hooks.cpp

@@ -162,7 +162,17 @@ HOOK_EXPORT EGLDisplay EGLAPIENTRY eglGetDisplay_renderdoc_hooked(EGLNativeDispl
   EnsureRealLibraryLoaded();
 
 #if ENABLED(RDOC_LINUX)
-  Keyboard::UseUnknownDisplay((void *)display);
+
+  // display can be EGL_DEFAULT_DISPLAY which is NULL, and unfortunately we don't have anything then
+  if(display)
+    Keyboard::UseUnknownDisplay((void *)display);
+
+// if xlib is compiled we can try to get the default display (which is what this will do)
+#if ENABLED(RDOC_XLIB)
+  else
+    Keyboard::UseUnknownDisplay(XOpenDisplay(NULL));
+#endif
+
 #endif
 
   return EGL.GetDisplay(display);

renderdoc/os/posix/linux/linux_stringio.cpp

@@ -509,6 +509,9 @@ bool GetWaylandKeyState(int key)
 
 WindowingSystem UseUnknownDisplay(void *disp)
 {
+  if(disp == NULL)
+    return WindowingSystem::Unknown;
+
   // could be wayland or xlib, try to detect.
   // both Display* and wl_display* are valid pointers, so dereference and read the first pointer
   // sized bytes