The dependency is either UTMPX or UTMP or Statgrab. The inclusion above hasn't statgrab.h in the elif-chain, that means compilation fails when only libstatgrab is available. The line can safely be taken out as the same condition is checked in #L120.
#elif HAVE_UTMP_H
# include <utmp.h>
/* #endif HAVE_UTMP_H */
#elif HAVE_UTMP_H
# include <utmp.h>
/* #endif HAVE_UTMP_H */
-
-#else
-# error "No applicable input method."
#endif
static void users_submit (gauge_t value)
#endif
static void users_submit (gauge_t value)