diff --git a/Makefile.inc1 b/Makefile.inc1
index 4172ea8bdc2c..7372b49c2737 100644
--- a/Makefile.inc1
+++ b/Makefile.inc1
@@ -332,7 +332,7 @@ KRNLCONFDIR=	${KRNLSRCDIR}/${MACHINE}/conf
 KRNLOBJDIR=	${OBJTREE}${KRNLSRCDIR}
 
 .if !defined(NOCLEAN)
-CONFIGARGS=	-r
+CONFIGARGS+=	-r
 .endif
 
 BUILDKERNELS=