Comment # 14 on bug 1171164 from Dr. Werner Fink

libutempter used by e.g. xterm

  /usr/lib64/libutempter.so.0
  /usr/lib64/libutempter.so.1.2.0
  /usr/libexec/utempter
  /usr/libexec/utempter/utempter

  strace -f -o log xterm

shows

 grep utempter/utempter log
 4615  execve("/usr/lib/utempter/utempter", ["/usr/lib/utempter/utempter",
"add", ":3"], 0x7ffd9e696598 /* 112 vars */) = -1 ENOENT (No such file or
directory)

suppose to use a utempter macro here .. or an autodetection at build time