diff --git a/lib/libc/net/Makefile.inc b/lib/libc/net/Makefile.inc
index 59cbdea4769..c6307afc1d5 100644
--- a/lib/libc/net/Makefile.inc
+++ b/lib/libc/net/Makefile.inc
@@ -34,11 +34,13 @@ CFLAGS+=-I${LIBC_SRCTOP}/resolv
 YFLAGS+=-p_nsyy
 LFLAGS+=-P_nsyy
 
-CLEANFILES+=nslexer.c
+CLEANFILES+=nslexer.c nslexer.c.*
 
 nslexer.c: nslexer.l nsparser.h
-	${LEX} ${LFLAGS} -o/dev/stdout ${.IMPSRC} | \
-		sed -e '/YY_BUF_SIZE/s/16384/1024/' >${.TARGET}
+	${LEX} ${LFLAGS} -o${.TARGET}.tmp1 ${.IMPSRC}
+	sed -e '/YY_BUF_SIZE/s/16384/1024/' ${.TARGET}.tmp1 >${.TARGET}.tmp2
+	rm -f ${.TARGET}.tmp1
+	mv -f ${.TARGET}.tmp2 ${.TARGET}
 
 MAN+=	byteorder.3 ethers.3 eui64.3 \
 	getaddrinfo.3 gai_strerror.3 gethostbyname.3 \