[gold][patch] Demangle a symbol only once per Version_script_info::get_symbol_version_helper call

[Ian Lance Taylor]

Mikolaj Zalewski <mikolajz@google.com> writes:

> Currently, this function is called for each version script entry. For
> libkhtml in KDE 3.5.10, this increased the CPU time by 50%.
>
> 2009-01-31  Mikolaj Zalewski  <mikolajz@google.com>
> 	* script.cc (Lazy_demangler): New class
>         (Version_script_info::get_symbol_version_helper): Demangle a
> symbol only once.

Approved and applied.

Thanks.

Ian