README.md

@@ -1,9 +1,11 @@
  # Welcome to the JDK!
  
- For build instructions, please see either of these files:
+ For build instructions, please see the
+ [online documentation](https://openjdk.java.net/groups/build/doc/building.html),
+ or either of these files:
  
- - [doc/building.html](https://openjdk.java.net/groups/build/doc/building.html) (html version)
+ - [doc/building.html](doc/building.html) (html version)
  - [doc/building.md](doc/building.md) (markdown version)
  
  See <https://openjdk.java.net/> for more information about
  the OpenJDK Community and the JDK.