>> There is no guarantee that `FlexLexer.h` found during compilation >> is the one that is used by a recent flex version. Unfortunately, >> `FlexLexer.h` doesn't contain any version information, so it is >> really impossible to protect against this situation automatically. > > Akim Demaille made a patch for it, see: > https://lists.gnu.org/archive/html/bug-bison/2018-09/msg00020.html
Nope, he didn't. This patch is for something completely different, as far as I can see – LilyPond doesn't use `FlexLexer.hh`, it rather uses `FlexLexer.h` that comes with flex. If you look into the git repository of flex you can see that even the most recent version of `FlexLexer.h` doesn't have any version information. Werner