elf/sprof.c (generate_call_graph): putchar_unlocked

[Roland McGrath]

> I don't fully understand the relationship between libio and stdio,
> except that stdio keeps getting out-of-date.  Is it supposed to be
> supported by glibc, or is it deprecated?

Both.  It is deprecated and will go away when it's no longer needed.
It is still the case that the Hurd needs stdio and doesn't work with libio.
This is one of the things that needs to be changed in the Hurd.

> Is the correct fix to change sprof.c, to modify stdio, or to ditch
> stdio entirely and just use libio?

The long term correct fix is the latter, but I don't think you are ready to
do that yet.  The Hurd code has some hairy uses of stdio.