int IdentifySourcePort()

Identifies the port the mod is being played in.

Returns one of the following constants:

• PORT_ZDOOM
• PORT_GZDOOM
• PORT_ZANDRONUM

The function performs the following checks:

1. If GetPlayerAccountName(0) returns a non-zero result (even an empty string), it is implemented and the port is assumed to be Zandronum.
2. If a DynamicLight actor can be spawned, the port is assumed to be GZDoom.
3. Otherwise it's ZDoom.