2.1 何故か最近ビルドする *-{releng,stable,current}で `uname -a' の表示がおかしい

• *-releng

  % uname -a
  FreeBSD tbedfr 12.0-RELEASE-p9 FreeBSD 12.0-RELEASE-p9 GENERIC \
      amd64
  % 
  

• *-stable

  % uname -a
  FreeBSD tbedfs 12.0-STABLE FreeBSD 12.0-STABLE GENERIC  amd64
  % 
  

• *-current

  % uname -a
  FreeBSD tbedfc 13.0-CURRENT FreeBSD 13.0-CURRENT r351108 GENERIC \
      amd64
  % 
  

• 普通は

  % uname -a
  FreeBSD smtp 13.0-CURRENT FreeBSD 13.0-CURRENT #0 r339677M: Fri \
      Oct 26 14:56:49 JST 2018 \
      root@msrvkx:/usr/obj/usr/src/amd64.amd64/sys/XIJ amd64
  %