[Bug c/87489] Spurious -Wnonnull warning

[andres at anarazel dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87489

--- Comment #2 from Andres Freund <andres at anarazel dot de> ---
Maybe (In reply to Jonathan Wakely from comment #1)
> The first XLogRegisterData could change the value of xl_xinfo.xid to be
> non-zero, in which case the second XLogRegisterData call would happen
> despite the null string.

Well, that'd then still only be a ok for a "may be" warning, not one that say
"argument 1 null where" (i.e. without a may be). Also, XLogRegisterData here
takes a const char * argument, so it really shouldn't modify the argument?