toolchain/53335: "fatal error: sys/proc.h: No such file or directory" occurs while running "build.sh tools"

[kiwamu%debian.or.jp@localhost]

>Number:         53335
>Category:       toolchain
>Synopsis:       "fatal error: sys/proc.h: No such file or directory" occurs while running "build.sh tools"
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    toolchain-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri Jun 01 03:20:00 +0000 2018
>Originator:     Kiwamu Okabe
>Release:        Date:   Thu May 31 20:52:53 2018 +0000
>Organization:
METASEPI DESIGN
>Environment:
Linux casper 4.16.0-1-amd64 #1 SMP Debian 4.16.5-1 (2018-04-29) x86_64 GNU/Linux

>Description:
Following error occurs on build.sh:

```
$ sh build.sh -U -u -j 4 -T obj/tooldir -m amd64 tools
--snip--
#    create  libctf/ctf_hash.d
/home/kiwamu/src/netbsd-src/obj/tooldir/bin/nbhost-mkdep -f ctf_hash.d.tmp  --      -DCTF_OLD_VERSIONS -I/home/kiwamu/src/netbsd-src/tools/libctf/../compat -I/home/kiwamu/src/netbsd-src/tools/ld
--- ctf_error.d ---
In file included from /home/kiwamu/src/netbsd-src/tools/libctf/../../external/cddl/osnet/sys/sys/param.h:32:0,
                 from /home/kiwamu/src/netbsd-src/tools/libctf/../../external/cddl/osnet/sys/sys/sysmacros.h:35,
                 from /usr/include/x86_64-linux-gnu/sys/types.h:205,
                 from /home/kiwamu/src/netbsd-src/tools/libctf/../../external/cddl/osnet/sys/sys/types.h:79,
                 from /home/kiwamu/src/netbsd-src/tools/libctf/../compat/compat_defs.h:35,
                 from /home/kiwamu/src/netbsd-src/obj/tooldir/include/compat/nbtool_config.h:882,
                 from /home/kiwamu/src/netbsd-src/tools/libctf/../../external/cddl/osnet/dist/common/ctf/ctf_error.c:23:
/home/kiwamu/src/netbsd-src/tools/libctf/../../external/cddl/osnet/sys/sys/proc.h:64:15: fatal error: sys/proc.h: No such file or directory
 #include_next <sys/proc.h>
               ^~~~~~~~~~~~
compilation terminated.
```
>How-To-Repeat:
$ sh build.sh -U -u -j 4 -T obj/tooldir -m amd64 tools
>Fix:
None