Add a weak symbol for cplus_demangle to libhpcrun.o for the static case.  This shouldn't be necessary and nothing actually uses it. But this was breaking hpclink.
Add a weak symbol for cplus_demangle to libhpcrun.o for the static
case.  This shouldn't be necessary and nothing actually uses it.
But this was breaking hpclink.

HPCToolkit/hpctoolkit,HPCToolkit/hpctoolkit,HPCToolkit/hpctoolkit,HPCToolkit/hpctoolkit,HPCToolkit/hpctoolkit,HPCToolkit/hpctoolkit