. remove some call cycles by low-level functions invoking printf(); e.g.
send_sig() gets a return value that the caller should check
. reason: very-early-phase printf() would trigger a printf() causing
infinite recursion -> GPF
. move serial initialization a little earlier so DEBUG_EXTRA works for
serial earlier (e.g. its first instance, for "cstart")
. closes tracker item 583:
System Fails to Complete Startup with Verbose 2 and 3 Boot Parameters,
reported by Stephen Hatton / pikpik.