Linux NaCl BPF sandbox : restrict clone()

Restrict clone() by defaulting to the baseline policy. This means that
fork() will EPERM and only the flags used by pthread_create() will be allowed.

BUG=367986
R=mseaborn@chromium.org

Review URL: https://codereview.chromium.org/272083002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@269167 0039d316-1c4b-4281-b951-d872f2087c98
1 file changed