anv: compile warnings with -Wpointer-arith
I use this flag (gcc) to ensure that I'm not accidentally my pointer maths, and anv (and other intel drivers to a lesser extent) generate over 1000 warnings every time I do a clean build. Any time the commit hash changes, it's another 50, which obscures any warnings in code I might actually have modified.
A lot of these seem like they're from inline functions in headers or the genX
magic, so it'd be great if at least those could be looked at.
Here's a (partial) log from a recent rebuild: https://pastebin.com/pM5dLrWc