Add support for the QNX operating system.

This patch contains contributions from the following members of the
BlackBerry Web Technologies team:

Eli Fidler <efidler@blackberry.com>
Konrad Piascik <kpiascik@blackberry.com>
Jeff Rogers <jrogers@blackberry.com>
Cosmin Truta <ctruta@blackberry.com>
Peter Wang <peter.wang@torchmobile.com.cn>
Xiaobo Wang <xiaobwang@blackberry.com>
Ming Xie <mxie@blackberry.com>
Leo Yang <leoyang@blackberry.com>

R=bmeurer@chromium.org, jkummerow@chromium.org

Review URL: https://codereview.chromium.org/61153009

Patch from Cosmin Truta <ctruta@blackberry.com>.

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@18430 ce2b1a6d-e550-0410-aec6-3dcde31c8c00