Functions differ only in their return type cannot be overloaded - Rebuild of the Debian archive with clang

"Functions differ only in their return type cannot be overloaded" build failure(s)
clang 6.0

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
cwidget	0.5.17-10	toplevel.cc:1059:28: error: functions that differ only in their return type cannot be overloaded	Log

1 errors

Debian Package rebuild