Move ComputationId inside SharedData.

This way it is avaiable right after the connection to coordinator has
been established.

git-svn-id: svn://svn.code.sf.net/p/dmtcp/code/trunk@2674 ba6dc0ae-232f-0410-883f-9ebac64fc565
Readded ptrace specific code

The ptrace specific behavior should be made default after further
testing.

git-svn-id: svn://svn.code.sf.net/p/dmtcp/code/trunk@2675 ba6dc0ae-232f-0410-883f-9ebac64fc565
Add gdb/strace tests on x86/x86_64 hosts.

git-svn-id: svn://svn.code.sf.net/p/dmtcp/code/trunk@2676 ba6dc0ae-232f-0410-883f-9ebac64fc565