This is a regression introduced with the commit https://bugs.webkit.org/show_bug.cgi?id=197131
The WPE Qt port was not updated to C++17 and this leaded to a compilation error.
In file included from DerivedSources/ForwardingHeaders/wtf/HashTraits.h:28,
DerivedSources/ForwardingHeaders/wtf/Optional.h:322:68: error: expected ‘)’ before ‘,’ token
template <class... Args> explicit Optional_base(std::in_place_t, Args&&... args)
Full log here https://paste.ubuntu.com/p/nvWmBjpq65/
I'm going to upload a patch for this.
Created attachment 368563 [details]
Comment on attachment 368563 [details]
Clearing flags on attachment: 368563
Committed r245516: <https://trac.webkit.org/changeset/245516>
All reviewed patches have been landed. Closing bug.