A make builtin and 21 everyday commands

make is now a builtin: a GNU make 4.3 subset with every assignment flavor, conditionals, define, include, explicit, pattern and suffix rules, functions such as foreach, call, wildcard and shell, and the options -f -C -n -k -q -s -i -B -e -j (-j runs sequentially). Recipes run through the sandbox shell, and messages and exit codes follow GNU make.

Twenty-one commands that used to report “command not found” are added: arch, sum, shasum, egrep, fgrep, link, unlink, chgrp, nohup, nice, flock, getconf, tty, sync, hostid, groups, logname, users, who, uptime and free. cmd N>file with N of 3 or more now opens only fd N.

See the compatibility scorecard, #2551 and #2546.