Remove unnecessary _Static_asserts

The C specifications already guarantees the offset of the first member
of a struct is 0.
Use +=
drm: Remove drm_drawable, move export to drm_draw_interface
drm: Add fallback dumb buffer support
intel: wld_intel_context -> intel_context
Add missing libdrm_CFLAGS
Remove some unnecessary newlines
intel: Adapt to libintelbatch changes
Switch to using Makefiles directly
Fix errors/warnings
Explicitly export symbols
Style: pixman_format -> format_wld_to_pixman
Move interface prototypes and struct declarations to interface/
Style
Add context abstraction
Style (#define FOO_H 1 -> #define FOO_H)
wld_draw_interface -> wld_drawable_impl
Rename wld_drm_interface -> drm_driver
drm: Add debug information about drivers tried
dumb: Support gem name importing