dlsym_default: fix compiler warnings.

git-svn-id: svn://svn.code.sf.net/p/dmtcp/code/trunk@2842 ba6dc0ae-232f-0410-883f-9ebac64fc565
JAlloc: Lock free allocation/deallocation

- Uses lock-free (linked list based) stack implementation.

git-svn-id: svn://svn.code.sf.net/p/dmtcp/code/trunk@2843 ba6dc0ae-232f-0410-883f-9ebac64fc565