1.0.1.24: unwinding lisp stack frames when alien code is doing a

1.0.1.24: unwinding lisp stack frames when alien code is doing a
          non-local exit.
  Revert src/assembly/x86/assem-rtns.lisp changes of version 1.0.0.19.
  Add Win32 SEH frame to catch-block and unwind-block object
    definitions.
  Changed VOPs in src/compiler/x86/nlx.lisp to set up SEH frames for
    unwind-protect and unwind targets.
  Added Win32-specific assembly-routines to handle unwinding and
    unwind-protect frames.
  Added an SEH frame to call_into_lisp.
  Added a wrapper around the runtime exception handler to provide a
    set of continuous stack frames over the system unwind logic (which
    doesn't maintain EBP properly, thus breaking backtraces).
  Added test cases for unwinding lisp stack frames from alien code.