HADOOP-12575. Add build instruction for docker toolbox instead of boot2docker. Contributed by Kai Sasaki.

BUILDING.txt

@@ -28,11 +28,11 @@ On Linux:
     $ ./start-build-env.sh
 
 On Mac:
-    First make sure Homebrew has been installed ( http://brew.sh/ )
-    $ brew install docker boot2docker
-    $ boot2docker init -m 4096
-    $ boot2docker start
-    $ $(boot2docker shellinit)
+    First make sure Virtualbox and docker toolbox are installed.
+    You can use docker toolbox as described in http://docs.docker.com/mac/step_one/.
+    $ docker-machine create --driver virtualbox \
+                            --virtualbox-memory "4096" hadoopdev
+    $ eval $(docker-machine env hadoopdev)
     $ ./start-build-env.sh
 
 The prompt which is then presented is located at a mounted version of the source tree

hadoop-common-project/hadoop-common/CHANGES.txt

@@ -965,6 +965,9 @@ Release 2.8.0 - UNRELEASED
     HADOOP-12582. Using BytesWritable's getLength() and getBytes() instead
     of get() and getSize(). (Akira AJISAKA via ozawa)
 
+    HADOOP-12575. Add build instruction for docker toolbox instead of
+    boot2docker(Kai Sasaki via ozawa)
+
   OPTIMIZATIONS
 
     HADOOP-11785. Reduce the number of listStatus operation in distcp