The X11 backend used System-V shared memory to communicate shared
buffers to the server, but rustix does not support SysV SHM so we had to
use libc in this backend. However, there is an alternate X11 API which
uses POSIX shared memory, which rustix does support. This PR switches
the X11 backend to POSIX shared memory and purges the previous
usages of libc.
The goal is to remove libc totally. Therefore this PR also removes the
default libc dependency from rustix.
Signed-off-by: John Nunley <dev@notgull.net>
Partly addresses
https://github.com/rust-windowing/softbuffer/issues/147, though it would
still be desirable to have a good safe API for SYSV shm in Rustix. But
using `libc` directly for now is no worse than using the `nix::libc`
re-export, so we don't lose anything.
This adds a DRM/KMS based backend to the system, as per #42. This system finds a CRTC and a connector, then uses that to create a frame buffer and a DUMB buffer that it can render to.
There's much more to do, and is left as an exercise for anyone with a significant DRM-based use case to pick up and fix.
Signed-off-by: John Nunley <dev@notgull.net>
