pkg/56873: xentools packages do not build on NetBSD-current

[gson%gson.org@localhost (Andreas Gustafsson)]

>Number:         56873
>Category:       pkg
>Synopsis:       xentools packages do not build on NetBSD-current
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    pkg-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Thu Jun 09 15:20:00 +0000 2022
>Originator:     Andreas Gustafsson
>Release:        NetBSD-current, source date 2022.06.08.13.08.44
>Organization:
  
>Environment:
System: NetBSD
Architecture: x86_64
Machine: amd64
>Description:

The xentools411, xentools413, and xentools415 packages all fail to
build on -current.  For example, the xentools413 build fails with
these error messages:

    xentoollog_stubs.c:57: error: "Some_val" redefined [-Werror]
       57 | #define Some_val(v) Field(v,0)
          | 
    In file included from /usr/pkg/lib/ocaml/caml/alloc.h:24,
                     from xentoollog_stubs.c:23:
    /usr/pkg/lib/ocaml/caml/mlvalues.h:404: note: this is the location of the previous definition
      404 | #define Some_val(v) Field(v, 0)
          | 
    cc1: all warnings being treated as errors

A tabular report showing all three failures is at

  https://www.gson.org/netbsd/bugs/xen/results/2022-06-09/index.html

>How-To-Repeat:

>Fix: