Assertion Failure when opening a map with a start point in the void
Description
If you open a map that has a starting location in null space (e.g. because you forgot to set it), the program crashes with an assertion failure: "Expression: (unsigned)sectnum < MAXSECTORS". In "source/build/src/engine.cpp" line 8687.
Since that is an easy-to-make mapping error, I feel that should be handled more cleanly.
This is for NetDuke32, but applies for EDuke32 too.
Reproduction
Create any map with the start location outside of a valid sector, then attempt to load it as a user map in the game
Priority
4 (Low) - caused by mapper error and the alternative would probably be a cleaner crash or dropping to console.
Additional Notes
Presumably sectnum
got set to -1 or is equal to MAXSECTORS
due to a for-loop not finding a sector that encapsulates the start point.