[Bug bootstrap/78616] [7 regression] bootstrap fails for x86_64-darwin at stage1 after 243030 when the bootstrap compiler doesn't have strndup

[iains at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78616

--- Comment #2 from Iain Sandoe <iains at gcc dot gnu.org> ---
(In reply to David Malcolm from comment #1)
> If I'm reading things right, it looks like libiberty provides an
> implementation of strndup if it's not available, but it doesn't provide a
> decl for it.

indeed
$ grep strndup include/libiberty.h 
extern char *xstrndup (const char *, size_t) ATTRIBUTE_MALLOC
ATTRIBUTE_RETURNS_NONNULL;

not sure exactly what the phasing is supposed to be.