* Make build crash with nghttp2
* Same for libpsl
* Output a message what's enforced now, so that everyone can catch up.
* Write the sed to finalize adjustment of pages in doc/:
  file named 'gnurl.1' should at least have the correct content, gnurl
  1 instead of curl 1.
* scripts/installcheck.sh,
  tests/certs/scripts/genroot.sh,
  tests/certs/scripts/genserv.sh,
  tests/fuzz/download_fuzzer.sh: Check for bashisms, fix if necessary.
  bash as invoked by /bin/sh works.
* convert groff pages to mdoc.