Changes since 23.7.0:
Prohibit vertical bar in COMMENT, to avoid generating syntactically wrong INDEX files.
Explain in which cases a distinfo file is not needed.
Fix detection of redundant trailing semicolon at the end of a command line. A semicolon that is escaped is not redundant, this pattern is often found in find commands.
Recognize indirect modifiers such as ${VAR:${M_indirect}}.