[uClibc] FINI processing moved to libc for x86

[Joakim Tjernlund]

> 
> I have just checked in a patch that move FINI handling from ldso to libc.
> Since this breaks API you must #define _DL_DO_FINI_IN_LIBC globally
> to actually enable this.
> All apps must be relinked with the new crtX.o file to work properly. Failure
> to do so will probably result in SEGV when the app exits.
> 
> I am holding off PPC support a little while pending a minor ABI investigation.

PPC has been checked in as well.

All apps built with a toolchain as of now for PPC and x86 will be able to handle the
new FINI processing.

TODO:
   Prepare the remaining arches. I can't do this myself so the arch maintainers
   need to look at this.

   Set a date for enabling the new FINI processing. I am sure Erik will
   have an idea here.