add missing @ (see bug #1302)

Makefile

@@ -76,7 +76,7 @@ check-packages :
 	     exit 1; \
 	  fi \
 	done
-	if test ! -e libraries/base/configure; then \
+	@if test ! -e libraries/base/configure; then \
 	    echo "Looks like you're missing base's configure script."; \
 	    echo "Did you run 'sh boot' at the top level?"; \
 	    exit 1; \