* hurd/hurdsig.c (_hurd_internal_post_signal): For SIGNO==0 pending
check, deliver a pending blocked signal if its action might be to
ignore.
* sysdeps/mach/hurd/sigaction.c: If new action is SIG_IGN or SIG_DFL
and SIG is pending, wake up signal thread to check us.
* hurd/hurdsig.c (_hurd_internal_post_signal): Don't mark a signal
pending while blocked or stopped when the action is to ignore it.
* hurd/hurdsig.c (_hurd_internal_post_signal: resume): Only set
SS_SUSPENDED when the thread is really suspended.
* elf/rtld.c (dl_main): Don't dereference _dl_rtld_map.l_next if null.