Polishing of the new trace2 facility continues. The system-level
configuration can specify site-wide trace2 settings, which can be
overridden with per-user configuration and environment variables.
* jh/trace2-sid-fix:
trace2: fixup access problem on /etc/gitconfig in read_very_early_config
trace2: update docs to describe system/global config settings
trace2: make SIDs more unique
trace2: clarify UTC datetime formatting
trace2: report peak memory usage of the process
trace2: use system/global config for default trace2 settings
config: add read_very_early_config()
trace2: find exec-dir before trace2 initialization
trace2: add absolute elapsed time to start event
trace2: refactor setting process starting time
config: initialize opts structure in repo_read_config()
5b2d1c0c6e