+dnl ---------- usleep ----------
+dnl --- stolen from guile configure ---
+dnl --- FIXME: /usr/include/unistd.h can't be right?
+
+### On some systems usleep has no return value. If it does have one,
+### we'd like to return it; otherwise, we'll fake it.
+AC_CACHE_CHECK([return type of usleep], cv_func_usleep_return_type,
+ [AC_EGREP_HEADER(changequote(<, >)<void[ ]+usleep>changequote([, ]),
+ /usr/include/unistd.h,
+ [cv_func_usleep_return_type=void],
+ [cv_func_usleep_return_type=int])])
+case "$cv_func_usleep_return_type" in
+ "void" )
+ AC_DEFINE(USLEEP_RETURNS_VOID, 1,
+ [Define if the system headers declare usleep to return void.])
+ ;;
+esac
+