[Ohrrpgce] SVN: teeemcee/10769 When increasing the zoom without changing the window size, enforce a min

[subversion at HamsterRepublic.com]

teeemcee
2018-10-19 05:10:25 -0700 (Fri, 19 Oct 2018)
662
When increasing the zoom without changing the window size, enforce a minimum resolution of 320x200

This was already apparently implemented, in gfx_sdl, but it didn't actually
work. E.g. if the resolution was 320x200 and you increased the zoom using
Custom's F9 menu, the window size wouldn't increase.

I fixed it and moved this logic into allmodex so it can be shared between
backends.

Note: there is still a bug in SDL/gfx_sdl where SDL (under X11) sometimes sends
a spurious SDL_VIDEORESIZE event causing the window to revert to its previous
size, screwing things up badly. Apparently because set_scale_factor causes
multiple SDL_SetVideoMode calls in a row
---
U   wip/allmodex.bas
U   wip/gfx_sdl.bas