vim-patch:7.4.1658

Problem:    A plugin does not know when VimEnter autocommands were already
            triggered.
Solution:   Add the v:vim_did_enter variable.

1473551a44

src/nvim/eval.h

@@ -124,6 +124,7 @@ typedef enum {
     VV_NULL,
     VV__NULL_LIST,  // List with NULL value. For test purposes only.
     VV__NULL_DICT,  // Dictionary with NULL value. For test purposes only.
+    VV_VIM_DID_ENTER,
 } VimVarIndex;
 
 /// All recognized msgpack types