define: DUK_OPT_UNDERSCORE_SETJMP
introduced: 1.1.0
removed: 1.5.0
tags:
  - portability
description: >
  Force _setjmp/_longjmp for long control transfers.  This ensures signal
  mask is not saved which can be a lot faster if setjmp/longjmp saves the
  signal mask (this varies between platforms).  See comments in
  DUK_OPT_SETJMP.