Add back 'android' and 'ios' for is_posix, and fix check for bsd.

BUG=none
R=thakis@chromium.org

Review URL: https://codereview.chromium.org/135273011

git-svn-id: http://grit-i18n.googlecode.com/svn/trunk@149 7262f16d-afe8-6277-6482-052fa10e57b1