Generate call graphs from C code

Current versions

Formula history

ilovezfs Indentation style fixes (#19679)
ilovezfs Use “squiggly” heredocs.
ilovezfs cflow: swap GNU url and mirror.
Dominyk Tiller urls: update ftpmirror to use https
Tomasz Pajor cflow 1.5
Nikolaus Wittenstein Add descriptions to all remaining homebrew packages
Dominyk Tiller cflow: modernise & add test