Use exlicit make targets, not directory contents.

net.Linux/Makefile

@@ -1,5 +1,7 @@
-DIR = ${RC_LIB}/net
-INC = ${CONTENTS}
+DIR=	${RC_LIB}/net
+INC=	adsl.sh apipa.sh arping.sh bonding.sh br2684ctl.sh ccwgroup.sh \
+	clip.sh ifconfig.sh ifplugd.sh ip6to4.sh ipppd.sh iproute2.sh \
+	iwconfig.sh netplugd.sh pppd.sh pump.sh tuntap.sh udhcpc.sh vlan.sh
 
 MK=	../mk
 include ${MK}/scripts.mk