#!/bin/bash

find . -name '*.ly' -exec sed '
  s/^.*\bifdef(`\([^'"'"']\+\)'"'"',.*$/\1/
  t
  d
' '{}' + \
| sort -u \
| sed '
  s/^STR_//
  t
  /^mit-/ p
  d
' \
| tr '\n' '-' \
| sed '
  s@-$@@
  s@^@-@
'