[Ohrrpgce] SVN: teeemcee/11293 Deduplicate win_error(), get_windows_error(), LastErrorString() into win

[subversion at HamsterRepublic.com]

teeemcee
2019-09-01 08:04:17 -0700 (Sun, 01 Sep 2019)
209
Deduplicate win_error(), get_windows_error(), LastErrorString() into win_error_str()

The new function lives in new gfx_common/win_error.c file, because that's where
some other code shared with gfx_directx is.
---
U   wip/SConscript
A   wip/gfx_common/win_error.c
U   wip/gfx_directx/gfx_directx.cpp
U   wip/lib/SDL/SDL_windowsclipboard.c
U   wip/misc.h
U   wip/os.bi
U   wip/os.h
U   wip/os_sockets.c
U   wip/os_windows.bas
U   wip/os_windows2.c