toolchain/59659: ctfconvert in tools is built differently on non-NetBSD OSes

[ozaki-r%iij.ad.jp@localhost]

>Number:         59659
>Category:       toolchain
>Synopsis:       ctfconvert in tools is built differently on non-NetBSD OSes
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    toolchain-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Thu Sep 18 09:45:00 +0000 2025
>Originator:     Ryota Ozaki
>Release:        current and 10 (probably also 11)
>Organization:
IIJ
>Environment:
amd64 and aarch64 (see below)
>Description:
ctfconvert is built as a tool with the NetBSD specific change that omits low-value CTF entries: "volatile", "const" and "restrict" (*).

(*) https://github.com/NetBSD/src/blob/f17778d50731ed4f8f4d2b5e817e979064019bc5/external/cddl/osnet/dist/tools/ctf/cvt/fixup_tdescs.c#L280-L288

Unfortunately, this change is applied inside #ifdef __NetBSD__ and so if it is built on non-NetBSD OS like Linux, the change is ignored. This results in that built binaries between NetBSD and Linux have different CTF data.
>How-To-Repeat:
Build NetBSD on both NetBSD and Linux, run ctfdump netbsd.gdb of both and see the differences of the outputs.

An example of sdiff output of the outputs (partial):
  total number of volatile types      = 0             |   total number of volatile types      = 41
  total number of const types         = 0             |   total number of const types         = 1017
  total number of restrict types      = 0             |   total number of restrict types      = 4

The left is NetBSD and the right is Linux.

Tested versions:
- NetBSD current (amd64) on NetBSD 9 (amd64)
- NetBSD 10 (aarch64) on NetBSD 9 (amd64)
- NetBDS 10 (aarch64) on Ubuntu 24.04 (amd64)
>Fix:
Add another condition HAVE_NBTOOL_CONFIG_H to #ifdef __NetBSD__ in fixup_tdescs.c.