libgnt/libgnt

Make all destroy functions multi-call safe.

2020-09-27, Elliott Sales de Andrade
ffb6069167a2
Make all destroy functions multi-call safe.

Also, fix an incorrect name for a dispose vfunc.

Testing Done:
Compile only, and the test from LIBGNT-11.

Reviewed at https://reviews.imfreedom.org/r/141/
[general]
shadow = 0
[colors]
black = 0; 0; 0
red = 1000; 0; 0
green = 0; 1000; 0
blue = 250; 250; 700
white = 1000; 1000; 1000
gray = 700; 700; 700
darkgray = 256; 256; 256
[colorpairs]
normal = black; white
highlight = white; blue
highlightd = black; gray
shadow = black; darkgray
title = white; blue
titled = white; gray
text = white; blue
disabled = gray; white