Gentoo's Bugzilla –
Attachment 863744 Details for
Bug 908419dev-qt/qtwebengine-5.15.9_p20230505 fails to build(lto):release/../../../../qtwebengine-5.15.9_p20230505/src/3rdparty/chromium/base/memory/ref_counted.h:145:19:error:type ‘struct RefCountedThreadSafeBase’ violates the C++ One Definition Rule [-Werror=odr]