www/webkit2-gtk4 fails to build on STABLE-13/amd64

Hi,

I recently updated my STABLE-13/amd64 host, and now it fails to build 
www/webkit2-gtk4; failing with:

/construction/xports/www/webkit2-gtk4/work/webkitgtk-2.38.3/Source/WTF/wtf/Function.h:79:26: 
warning: unused parameter 'in' [-Wunused-parameter]
     Out operator()(In... in) const
                          ^
/construction/xports/www/webkit2-gtk4/work/webkitgtk-2.38.3/Source/WTF/wtf/URLHelpers.cpp:51:34: 
error: integer value 256 is outside the valid range of values [-
256, 255] for the enumeration type 'UScriptCode' 
[-Wenum-constexpr-conversion]
constexpr auto scriptCodeLimit = static_cast<UScriptCode>(256);
                                  ^
2 warnings and 1 error generated.

I notice that Muhammad Moinur Rahman had recently made a commit to 
webkit2-gtk4/Makefile to enable llvm16 support, probably for the main 
branch. This also needs to be enabled for stable/13 which now has llvm16 
as its host-compiler.

Cheers.
-- 
Jonathan Chen <jonc@chen.org.nz>