vcc: error check in vcc_walksymbols() for the recursive case

Bail out upon first error, as for the non-recursive case.

lib/libvcc/vcc_symb.c

@@ -445,6 +445,7 @@ vcc_walksymbols(struct vcc *tl, const struct symtab *root,
 			assert(strcasecmp(st1->name, st2->name) >= 0);
 		st2 = st1;
 		vcc_walksymbols(tl, st1, func, kind);
+		ERRCHK(tl);
 	}
 }