--- Mk/bsd.port.mk	(revision 402649)
+++ Mk/bsd.port.mk	(working copy)
@@ -2526,7 +2526,7 @@ 
 master-sites: master-sites-DEFAULT
 patch-sites: patch-sites-DEFAULT
 
-CKSUMFILES=		${ALLFILES}
+CKSUMFILES+=		${ALLFILES}
 
 # List of all files, with ${DIST_SUBDIR} in front.  Used for checksum.
 .if defined(DIST_SUBDIR)