done a dozen of randconfig test. guess what? ALL failed...

these are resulting fixes

coreutils/chgrp.c

@@ -13,6 +13,9 @@
 
 #include "busybox.h"
 
+/* FIXME - move to .h */
+extern int chown_main(int argc, char **argv);
+
 int chgrp_main(int argc, char **argv)
 {
 	/* "chgrp [opts] abc file(s)" == "chown [opts] :abc file(s)" */

coreutils/diff.c

@@ -71,7 +71,7 @@ int context, status;
 char *start, *label[2];
 struct stat stb1, stb2;
 char **dl;
-static int dl_count;
+USE_FEATURE_DIFF_DIR(static int dl_count;)
 
 struct cand {
 	int x;