Wrong C++ default declaration in a method - Rebuild of the Debian archive with clang

"Wrong C++ default declaration in a method" build failure(s)
clang 13.0.0

The default argument must be set in the definition or the definition done in the method declaration.

class string
{
    friend string foo(int bar = 0);
};

Versions: 2.9 - 3.0 - 3.1 - 3.2 - 3.3 - 3.4 - 3.4.2 - 3.5.0 - 3.6.0 - 3.8.1 - 3.9.1 - 4.0.1 - 5.0 - 6.0 - 8.0.1 - 9.0.1 - 10.0.0 - 11.0.0 - 12.0.1 - 13.0.0

Package	Version	Supposed error message	Full log	Bug report
wp2latex	3.100+ds-2	../atoms/include/stringa.h:191:23: error: friend declaration specifying a default argument must be a definition	Log

1 errors

Debian Package rebuild