[RFC PATCH 1/2] dlfcn: add long double redirect wrappers for dl*sym

[Florian Weimer]

* Paul E. Murphy via Libc-alpha:

> Using a non-default long double creates some odd issues when
> attempting to dynamically load symbols.  I am not sure how
> big an issue this really is, but it is worth putting forth
> patches to have this discussion.  Users of the IEEE128 ldbl
> will run into ABI problems if they attempt to load symbols
> which are renamed (mangled via asm redirects).  A first
> attempt here is to mangle lib{c,m,dl} symbol names which are
> redirected via headers by wrapping dl*sym functions.  Given
> that the renames are not always trivial and may grow with
> future releases, this is something the end user should not
> have to do.

We have seen such problems only with underlinking, not with dlsym.  But
that may be because for the other targets that underwent the transition,
version-less dlsym lookups point to the most recent version, which has
the default long double.

Thanks,
Florian