Bump to v4.16.4.

_baseToString.js

@@ -1,4 +1,6 @@
 var Symbol = require('./_Symbol'),
+    arrayMap = require('./_arrayMap'),
+    isArray = require('./isArray'),
     isSymbol = require('./isSymbol');
 
 /** Used as references for various `Number` constants. */
@@ -21,6 +23,10 @@ function baseToString(value) {
   if (typeof value == 'string') {
     return value;
   }
+  if (isArray(value)) {
+    // Recursively convert values (susceptible to call stack limits).
+    return arrayMap(value, baseToString) + '';
+  }
   if (isSymbol(value)) {
     return symbolToString ? symbolToString.call(value) : '';
   }