Further cleanup of ps_status setup code. On platforms where the

Further cleanup of ps_status setup code.  On platforms where the
environment strings need to be moved around, do so when called from
initial startup (main.c), not in init_ps_status.  This eliminates the
former risk of invalidating saved environment-string pointers, since
no code has yet had a chance to grab any such pointers when main.c
is running.