* Get rid of the RCS Header stuff.  They're meaningless in git.
 * Add public domain comment to some of the files if the only comment
   was the RCS header.

lisp.c into the correct <foo>-os.h files.

  o Move the SC_OFFSET_{HI,LO} macros from sparc-lispregs to
    lispregs.h, so they can be used elsewhere.

ppc-lispregs.h:
  o Define the register numbers so they can be used in the SC_OFFSET
    macros.

ppc-assem.S:
  o Document what the byte 18<<2, 0, 0, 24 is supposed to do.
  o Use the SC_OFFSET macros in undefined_tramp instead of hard-wiring
    the register number.

versions of all the required things, this commit separates the
interrupt handler proper (now interrupt_handle_now_handler) from the
actual work-horse (interrupt_handle_now), which is now only ever called
from the two interrupt handlers, interrupt_handle_now_handler and
maybe_now_maybe_later.  This follows similar changes in SBCL, and is in
fact needed in order to properly use sigreturn in signal handlers, as
required to work around a problem with the G5.

platform assembler code can use those, instead of magic numbers and
bogus conditionalization on type_Long_Float.  Inspired/Stolen from
SBCL.  Also added some more comments in places, and a generic
SC_OFFSET macro that matches lisp/debug-info.lisp.

address in the LIP.  Also changed the name of CONT to CSP and OLDCONT to
OCFP.