* libgcc2.c (top_elt): Remove top_elt, it isn't thread safe.
The strategy we now use is to pre allocate the top_elt along
with the EH context so that each thread has its own top_elt.
This is necessary as the dynmanic cleanup chain is used on the
top element of the stack and each thread MUST have its own.
(eh_context_static): Likewise.
(new_eh_context): Likewise.
(__sjthrow): Likewise.
From-SVN: r23818
