- AC_SEARCH_LIBS(nanosleep, [rt posix4], [LIB_NANOSLEEP=$ac_cv_search_nanosleep])
- AC_SUBST(LIB_NANOSLEEP)
+ AC_SEARCH_LIBS([nanosleep], [rt posix4],
+ [test "$ac_cv_search_nanosleep" = "none required" ||
+ LIB_NANOSLEEP=$ac_cv_search_nanosleep])
+ AC_SUBST([LIB_NANOSLEEP])