[PATCH 2/2] Only provide non-default symbols in libpthread for vfork

[Roland McGrath]

We need to separately decide about if/how we want to rely on the attribute
support as I mentioned a moment ago in the other thread.  But to proceed as
if we'll decide to rely on the attribute in all our IFUNC-defining C code:

> +void *vfork_ifunc(void *, const void *, size_t)
> +     __attribute__ ((ifunc ("vfork_resolve")));

What in carnation is that signature?  (And it needs a space.)
A pasto from a memcpy implementation, I guess?

Does it not work to do:
	__typeof (vfork) vfork_ifunc __attribute__ ((ifunc ("vfork_resolve")));
?

Obviously this case has the most trivial of signatures.  But I'm thinking
about if we can maybe define a macro or two for this stuff and clean up
all our IFUNC stuff to look actually somewhat pretty.

>  #if SHLIB_COMPAT (libpthread, GLIBC_2_1_2, GLIBC_2_20)
> -DEFINE_VFORK (__vfork)
> +strong_alias (vfork_ifunc, vfork_ifunc2)
> +compat_symbol (libpthread, vfork_ifunc2, __vfork, GLIBC_2_1_2);
>  #endif

For some reason "ifunc2" just really irks me.  I'd rather see
__vfork_ifunc, as if we had a straightforward convention that the
STV_HIDDEN name of foo's IFUNC symbol is foo_ifunc.


Thanks,
Roland