Fix bad rule and bad dependency for nsparser.h that can

cause the build to fail because y.tab.c can have a more
recent modification time than y.tab.h, and the bad rule
relied on the opposite.

(The last write to y.tab.c by yacc(1) happens after the
last write to y.tab.h, according to truss(1).)

Reported by:	kensmith

lib/libc/net/Makefile.inc

@@ -12,7 +12,7 @@ SRCS+=	base64.c ether_addr.c eui64.c \
 	getproto.c getprotoent.c getprotoname.c getservent.c \
 	if_indextoname.c if_nameindex.c if_nametoindex.c \
 	ip6opt.c linkaddr.c map_v4v6.c name6.c ntoh.c \
-	nsdispatch.c nslexer.c nsparser.c nss_compat.c \
+	nsdispatch.c nslexer.c nsparser.y nss_compat.c \
 	rcmd.c rcmdsh.c recv.c rthdr.c sctp_sys_calls.c send.c \
         sockatmark.c sourcefilter.c vars.c
 
@@ -34,12 +34,9 @@ CFLAGS+=-I${.CURDIR}/resolv
 YFLAGS+=-p_nsyy
 LFLAGS+=-P_nsyy
 
-CLEANFILES+=nsparser.c nslexer.c nsparser.h
+CLEANFILES+=nslexer.c
 
-nsparser.h: nsparser.c
-	mv y.tab.h ${.TARGET}
-
-nslexer.c: nslexer.l nsparser.h
+nslexer.c: nslexer.l
 	${LEX} ${LFLAGS} -o/dev/stdout ${.IMPSRC} | \
 		sed -e '/YY_BUF_SIZE/s/16384/1024/' >${.TARGET}