+.SECONDARY: $(addsuffix _c.o, $(filter-out adnshost, $(CLIENTS)))
+# Without this, make will remove <client>_c.o after building <client>.
+# This wastes effort. (Debian bug #4073.)
+#
+# Also, it exposes us to a bug (in make 3.81, at least) which can
+# cause make to run the rule for building <client> without building
+# <client>_c.o! (Debian #756123.)
+#
+# See also Savannah #29620, http://savannah.gnu.org/bugs/index.php?29620
+