This convenience routine simplifies creating and properly
    initializing an invocation context block. Users of this routine
    should call LIB$X86_FREE_INVO_CONTEXT when the invocation
    context block is no longer required. This routine sets the
    cache unwind flag LIBICB$V_UO_FLAG_CACHE_UNWIND in the
    invocation context block to speed the stack walk. Do not use
    this routine in conjunction with LIB$X86_INIT_INVO_CONTEXT,
    because the same initialization is performed by both routines.

    Format

      LIB$X86_CREATE_INVO_CONTEXT ([malloc] [, free] [, ident])