GitLab

If the enviroment variable SKIA_OUT is set the output of both
gyp and make will be redirected to that directory.

Review URL: https://codereview.appspot.com/6782095

git-svn-id: http://skia.googlecode.com/svn/trunk@6578 2bbb7eff-a529-9590-31e7-b0007b416f81