When compiling with clang-cl the WinCairo build fails with

..\..\Source\WebCore\html\canvas\WebGLDrawBuffers.cpp(77,29): error: non-constant-expression cannot be narrowed from type 'WebCore::GraphicsContextGL::(anonymous enum at ..\..\Source\WebCore\platform\graphics\GraphicsContextGL.h:64:5)' to 'GCGLenum' (aka 'unsigned int') in initializer list [-Wc++11-narrowing]
        GCGLenum value[1] { (bufs[0] == GraphicsContextGL::BACK) ? GraphicsContextGL::COLOR_ATTACHMENT0 : GraphicsContextGL::NONE };
                            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
..\..\Source\WebCore\html\canvas\WebGLDrawBuffers.cpp(77,29): note: insert an explicit cast to silence this issue
        GCGLenum value[1] { (bufs[0] == GraphicsContextGL::BACK) ? GraphicsContextGL::COLOR_ATTACHMENT0 : GraphicsContextGL::NONE };
                            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
                            static_cast<GCGLenum>(                                                                               )