Pass _dl_fini function ptr to __uClibc_start_main().
Pass _dl_fini function ptr to __uClibc_start_main().

To actually use it, one must define _DL_DO_FINI_IN_LIBC globally.
That will also break ABI for apps linked with previous version of crtX.S.
They must be relinked with this version to work again.

joel-porquet/tsar-uclibc,joel-porquet/tsar-uclibc,joel-porquet/tsar-uclibc,joel-porquet/tsar-uclibc