It seems this build caused the build failure, but these are unrelated changes: https://build.webkit.org/builders/WinCairo%2064-Bit%20Release/builds/53844 build error: Vector.cpp.obj : error LNK2001: unresolved external symbol __imp_WTFCrashImpl WorkQueue.cpp.obj : error LNK2001: unresolved external symbol __imp_WTFCrashImpl MetaAllocator.cpp.obj : error LNK2001: unresolved external symbol __imp_WTFCrashImpl ParkingLot.cpp.obj : error LNK2001: unresolved external symbol __imp_WTFCrashImpl RedBlackTree.cpp.obj : error LNK2001: unresolved external symbol __imp_WTFCrashImpl StringOperators.cpp.obj : error LNK2001: unresolved external symbol __imp_WTFCrashImpl Condition.cpp.obj : error LNK2001: unresolved external symbol __imp_WTFCrashImpl CheckedArithmeticOperations.cpp.obj : error LNK2001: unresolved external symbol __imp_WTFCrashImpl Deque.cpp.obj : error LNK2001: unresolved external symbol __imp_WTFCrashImpl IntegerToStringConversion.cpp.obj : error LNK2001: unresolved external symbol __imp_WTFCrashImpl bin64\TestWTFLib.dll : fatal error LNK1120: 1 unresolved externals Maybe clean build could help, but the "force clean build" button completely kills the WinCairo bot - bug153876
It's green again after a completely unrelated change: https://build.webkit.org/builders/WinCairo%2064-Bit%20Release/builds/53939