It is a C-style assert causing application termination when triggered.
Certain systems display pcbnew window shrinked so much, that the canvas
size is 0x0 pixels. The only problem with that is the window needs to be
resized.
Fixes: lp:1767031
* https://bugs.launchpad.net/kicad/+bug/1767031
- support for background color setting
- removed several global config settings (such as g_Drc_On)
- wrapped most of global config settings in PCB_GENERAL_SETTINGS class
- reorganized PCB general options dialog to clearly mark which options concern only the legacy canvas
- new GAL feature for legacy users: double-click (or E) to change track width available as an option.
Fixes: lp:1530543
* https://bugs.launchpad.net/kicad/+bug/1530543
Fixes: lp:1707145
* https://bugs.launchpad.net/kicad/+bug/1707145