recode "typeinfo::name()" into usable format

[Grizlyk]

Hello.

If I print name of class at runtime, I can use "typeinfo::name()" like
this:
    printf( "%s\n", typeid(*this).name() );

And for class named "Tclass" I will get a unreadable g++ specific
formatted sring looks like
  "1P2N!@#...Tclass...!@#$"

Also it is well known, that std::unexpected() can print correct name of
class. What function of g++ does correct name demangling?