patch 7.4.1553
Problem:    ":runtime" does not use 'packpath'.
Solution:   Add "what" argument.
diff --git a/src/vim.h b/src/vim.h
index becc26a..9e4406a 100644
--- a/src/vim.h
+++ b/src/vim.h
@@ -2294,5 +2294,6 @@
 #define DIP_ERR	    0x04	/* give an error message when none found. */
 #define DIP_START   0x08	/* also use "start" directory in 'packpath' */
 #define DIP_OPT	    0x10	/* also use "opt" directory in 'packpath' */
+#define DIP_NORTP   0x20	/* do not use 'runtimepath' */
 
 #endif /* VIM__H */