[StephenOman]

NetHack 5 has refactored all global variables into alphabetical structures. For example, all global variables starting with the letter 'a' are now in a structure called ga (see decl.h:141 and decl.c:1085). Initialising these global variables is now controlled by individual functions, so that the game engine can be totally initialised. See decl.c:1080 for this initialisation function, called decl_globals_init.

For NLE purposes, this initialisation occurs after the original initialisation of the terminal dimensions in nle.c. This PR changes this as follows:

• moves the terminal dimension specification to the TMT initialisation on startup
• adds initialisation to gettty() for subsequent calls to the terminal. Adding it here in nle.c avoids changes in NetHack code.

Note: This NetHack 5 change opens the possibility for simplifying multiple runs of the game engine as the global variables could be reinitialised. This is out of the scope for NH5 upgrade.

[heiner]

This NetHack 5 change opens the possibility for simplifying multiple runs of the game engine as the global variables could be reinitialised.

This is excellent! It means no dlopen/dlclose to reinitialize, which likely makes episode restarts a good deal faster.