sdl2: use alt+f4 to send SDL_QUIT event
sdl2: allow Unicode (besides 9 priv space) as text input event, fix priv space keys when text input is enabled
default to 256k stack for threads
sdl2: clean up includes
plan9.h: include stddef.h directly here, also thread.h if threaded version is used
sdl2: define and use SDL_TEXTINPUTEVENT_TEXT_SIZE for text input events
move exit(3) to plan9.h, choose between threadexitsall and exits depending on __plan9_keep_main__
make "main" function overriding optional
link the guide in the readme
limits: increase PATH_MAX to 4096
getenv: map XDG_* and USER variables to something
relax includes. again.
move custom getenv into the main header
SDL_RenderCopy: fall back to memimagedraw if no stretching done
rearrange and rename to avoid conflicts
sdl2: mouse: support middle button
add sigaction
update readme
build & install as syslibs
dump it to git so I do not lose anything