Reviewed-by: Eric Anholt <eric@anholt.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/6894>
- glGet*(GL_DEPTH_BITS) returned bytes, not bits
- point, line, and bitmap rasterization suffered from roundoff errors
-- fixed a division by zero error in line clippping
+- fixed a division by zero error in line clipping
- occasional wrong default background color really fixed!
- glDepthFunc(GL_ALWAYS) with glDepthMask(GL_FALSE) didn't work
- gluBuild2DMipmaps malloc problem fixed