Allow unpriviledged gdbserver to attach to debuggable processes.
This patch is used to allow an unprivileged gdbserver binary to
perform a ptrace attach to a debuggable process.
The kernel will only allow the attach to succeed under the following
conditions:
- gdbserver and the process are run under the exact same uids/gids
- the process is dumpable
The second condition requires this patch. The first one is ensured
by different changes to the platform (that don't directly touch Dalvik).
This is part of the work performed to allow native debugging of
applications on production devices.