Merge branch 'jk/bug-to-abort' into maint

Introduce the BUG() macro to improve die("BUG: ..."). * jk/bug-to-abort: usage: add NORETURN to BUG() function definitions config: complain about --local outside of a git repo setup_git_env: convert die("BUG") to BUG() usage.c: add BUG() function