[Bug c++/86329] Bogus fix-it hint: note: suggested alternative: '._72'

[dmalcolm at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86329

--- Comment #1 from David Malcolm <dmalcolm at gcc dot gnu.org> ---
Confirmed on trunk, gcc-8, and gcc-7.
Doesn't affect gcc-6.

The bogus dotted names are coming from anonymous enums in the header; a more
minimal reproducer is:

enum {};

int test()
{
  return __0;
}

pr86329.C: In function ‘int test()’:
pr86329.C:5:10: error: ‘__0’ was not declared in this scope
   return __0;
          ^~~
pr86329.C:5:10: note: suggested alternative: ‘._0’
   return __0;
          ^~~
          ._0

I'm working on a fix.