--- ./Source/WebCore/CMakeLists.txt.orig	2020-12-28 10:09:15.029917333 +1000
+++ ./Source/WebCore/CMakeLists.txt	2020-12-28 11:15:45.474052232 +1000
@@ -3778,6 +3778,9 @@
     ADD_TARGET_PROPERTIES(WebCore COMPILE_FLAGS "-fno-tree-sra")
 endif ()
 
+# For some reason this is required on Linux now (TRUE/FALSE already defined on other platforms?)
+target_compile_definitions(WebCore PRIVATE U_DEFINE_FALSE_AND_TRUE=1)
+
 if (MSVC)
     ADD_PRECOMPILED_HEADER("WebCoreTestSupportPrefix.h" "testing/js/WebCoreTestSupportPrefix.cpp" WebCoreTestSupport_SOURCES)
 endif ()
