[patch] msvc demangling binutils

[lucio@proxima.alt.za]

> I think the way to do this would be to do a autoconf check for the 
> presence of the prototype of UnDecorateSymbolName in <dbghelp.h>, 
> presence of the UnDecorateSymbolName symbol in -ldbghelp, and a check 
> that an executable linked against this symbol in dbghelp will actually 
> run (to ensure the system actually has the DLL).

...  and suggest what to do if the functionality is not present but is
desired.  It sounds too good an option to miss through ignorance or
forgetfulness.

++L