even if you write signal handlers to not do anything stupid when you're

even if you write signal handlers to not do anything stupid when you're
not on a terminal, they STILL interrupt long system calls and cause sysread
to fail, so disable them when they're not needed.

problem found by mlarkin@

this is just a band-aid, I guess I really need to "reset" non-needed signals
globally whenever I fork... sigh.