Weird stuff happens

Five days ago, my buildfarm animal jacana suddenly started getting an error while trying to extract typedefs. It had been happily doing this for ages, and suddenly the quite reproducible error started. For now I have disabled its typedef analysis, but I will need to get to the bottom of it. It's bad enough to crash the buildfarm client leaving the build directory dirty and not able to process further builds until I clean it up. I'm assuming it's probably something that changed in the source code, as nothing else has changed at all. These are the commits that took place between a good run and the first appearance of the error.

• 9a83564 Allow SSL server key file to have group read access if owned by root
• 6eb2be1 Fix stupid omission in c4901a1e.
• 07aed46 Fix missed update in _readForeignScan().
• ff0a7e6 Use yylex_init not yylex_init_extra().
• a3e39f8 Suppress FLEX_NO_BACKUP check for psqlscanslash.l.
• 0ea9efb Split psql's lexer into two separate .l files for SQL and backslash cases.

 I don't know for dead certain that any of these has caused an issue, but finding out what the problem is is just one more way for me to spend my copious free time.