(_dl_rpath): New variable.

(_dl_rpath): New variable.
(_dl_start): Set it from rtld_map's DT_RPATH.
Call _dl_setup_hash on rtld_map.
(dl_main): Cache address of _exit in variable before relocating, and use
that in later calls.  Call _dl_sysdep_start_cleanup before relocating.
Keep track of dependency order while loading; remove rtld_map from chain,
and reinsert in proper order if there is a dependency on it.