[Bug modula2/116123] flex generated files should be committed to the tree so that flex is not needed on build

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116123

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
https://gcc.gnu.org/install/prerequisites.html


Flex version 2.5.4 (or later)
Necessary when modifying *.l files.

Necessary to build GCC during development because the generated output files
are not included in the version-controlled source repository. They are included
in releases.