[GR-2798] Fix "managed" build (2).

com.oracle.truffle.r.native/library/base/Makefile

@@ -52,7 +52,7 @@ post.done:
 # rebuild GNU R in compressed mode
 	(cd $(GNUR_HOME); $(MAKE))
 	touch post.done
-	find $(FASTR_LIBRARY_DIR)/base -type f -exec touch {} +
+	find $(FASTR_LIBRARY_DIR)/base -exec touch {} +
 
 clean.done:
 	rm -f post.done pre.done