[Ohrrpgce] SVN: teeemcee/12437 gfx_sdl2: fix 3 fairly minor window resizability problems

[subversion at HamsterRepublic.com]

teeemcee
2021-09-14 07:53:55 -0700 (Tue, 14 Sep 2021)
584
gfx_sdl2: fix 3 fairly minor window resizability problems

-Toggling resizability state while fullscreened didn't work, so apply it
 when unfullscreening
-If you opened a debug menu in-game, resized the window, pressed alt-enter to
 fullscreen, exited the menu and then alt-entered back to windowed, the window
 didn't return to the correct (original) size.
-If a resize that we didn't want happened, it didn't get overridden, leaving
 the window with black space or partly cut off. That could happen the instant
 before we disable resizing, but haven't handled all resize events yet.
---
U   wip/gfx_sdl2.bas
U   wip/whatsnew.txt