expose preserveWhitespace option in template compiler

Author: yyx990803

packages/vue-template-compiler/README.md

@@ -57,6 +57,10 @@ The optional `options` object can contain the following:
 
   Refer to the implementation of some [built-in compile-time directives](https://github.com/vuejs/vue/tree/next/src/platforms/web/compiler/directives).
 
+- `preserveWhitespace`
+
+  Defaults to `true`. This means the compiled render function respects all the whitespaces between HTML tags. If set to `false`, all whitespaces between tags will be ignored. This can result in slightly better performance but may affect layout for inline elements.
+
 ---
 
 ### compiler.compileToFunctions(template)

src/entries/web-compiler.js

@@ -24,6 +24,7 @@ export function compile (
   const compiled = baseCompile(template, {
     modules,
     directives,
+    preserveWhitespace: options.preserveWhitespace,
     warn: msg => {
       errors.push(msg)
     }