Detect GNU Hurd and Debian kFreeBSD as ANGLE_OS_POSIX

See https://bugzilla.mozilla.org/show_bug.cgi?id=711353

Patch by Mike Hommey



git-svn-id: https://angleproject.googlecode.com/svn/trunk@954 736b8ea6-26fd-11df-bfd4-992fa37f6226
3 files changed