[Bug c++/91964] Wrong -Wint-in-bool-context warning for enum constant

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91964

--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> ---
The warning was introduced for PR 77434 and the current behaviour by the fix
for PR 77700.