crt0 uses a helper function in a MD src/libexec/ld.so .h file (rather than

crt0 uses a helper function in a MD src/libexec/ld.so .h file (rather than
reproducing the relevant defines and code in a different place) to perform
minor relocations.  If things go very wrong, it would call _dl_exit() --
a locally defined crt0 function which is syscall exit(2).  We don't need
to call exit(2) for this obscure case which doesn't happen and provides no
debugging information. An 'abort' is going to provide better information.
So let's change the function name to _dso_abort() and make it a single
illegal instruction.
ok guenther