util: always force line buffered stdout when stdout is a tty (BC) pager replaced stdout with a line buffered version to work around glibc deciding on a buffering strategy on the first write to stdout. This is going to make my next patch hard, as replacing stdout will make tracking time spent blocked on it more challenging. Move the line buffering requirement to util.py, and remove it from pager. This means that the abuse of ui.formatted=True and pager set to cat or equivalent no longer results in a line-buffered output to a pipe, hence (BC), although I don't expect anyone to be affected