make abs, wrapping_abs, and overflowing_abs const functions
make abs, wrapping_abs, and overflowing_abs const functions

aidancully/rust,graydon/rust,graydon/rust,aidancully/rust,aidancully/rust,aidancully/rust,graydon/rust,graydon/rust,graydon/rust,aidancully/rust,graydon/rust,aidancully/rust