This has been the case since before r156490. Some of the error messages: 20>..\platform\graphics\cg\GraphicsContextCG.cpp(843): error C3861: 'wkCGContextIsPDFContext': identifier not found 20>..\platform\graphics\cg\GraphicsContextCG.cpp(911): error C3861: 'wkCGContextDrawsWithCorrectShadowOffsets': identifier not found ... 20>c:\cygwin\home\trybot\webkit\opensource\source\webcore\rendering\RenderMediaControls.cpp(48): error C2660: 'WKHitTestMediaUIPart' : function does not take 3 arguments 20>c:\cygwin\home\trybot\webkit\opensource\source\webcore\rendering\RenderMediaControls.cpp(53): error C2660: 'WKMeasureMediaUIPart' : function does not take 3 arguments 20>c:\cygwin\home\trybot\webkit\opensource\source\webcore\rendering\RenderMediaControls.cpp(58): error C2660: 'WKDrawMediaUIPart' : function does not take 4 arguments 20>c:\cygwin\home\trybot\webkit\opensource\source\webcore\rendering\RenderMediaControls.cpp(63): error C2660: 'WKDrawMediaSliderTrack' : function does not take 6 arguments
This isn't a bug in the sources; it's a configuration problem on the Trybot. The version of WebKit you are building does not match the version of WebKitSystemInterface installed on the Trybot.