Index: head/tests/sys/kern/acct/Makefile
===================================================================
--- head/tests/sys/kern/acct/Makefile	(revision 291179)
+++ head/tests/sys/kern/acct/Makefile	(revision 291180)
@@ -1,17 +1,18 @@
 # $FreeBSD$
 
 TESTSDIR=	${TESTSBASE}/sys/kern/acct
 
 ATF_TESTS_C=	acct_test
 
 CFLAGS+=	-I${.OBJDIR}
 
-CLEANFILES+=	convert.c
+CLEANFILES+=	convert.c convert.c.tmp
 
 DPSRCS.acct_test=	convert.c
 
 convert.c: ${SRCTOP}/sys/kern/kern_acct.c
 	sed -n -e 's/log(/syslog(/g' \
-	       -e '/FLOAT_CONVERSION_START/,/FLOAT_CONVERSION_END/p' ${.ALLSRC} >>${.TARGET}
+	       -e '/FLOAT_CONVERSION_START/,/FLOAT_CONVERSION_END/p' ${.ALLSRC} >${.TARGET}.tmp
+	mv ${.TARGET}.tmp ${.TARGET}
 
 .include <bsd.test.mk>