diff -up webkitgtk-2.15.90/Source/cmake/OptionsCommon.cmake.gcc7 webkitgtk-2.15.90/Source/cmake/OptionsCommon.cmake
--- webkitgtk-2.15.90/Source/cmake/OptionsCommon.cmake.gcc7	2017-02-21 09:57:13.168916004 +0100
+++ webkitgtk-2.15.90/Source/cmake/OptionsCommon.cmake	2017-02-21 09:58:12.811563156 +0100
@@ -41,6 +41,8 @@ if (COMPILER_IS_GCC_OR_CLANG)
     set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -fno-exceptions -fno-strict-aliasing")
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fno-exceptions -fno-strict-aliasing -fno-rtti")
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++1y")
+    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -Wno-expansion-to-defined")
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-expansion-to-defined")
 endif ()
 
 if (COMPILER_IS_CLANG AND CMAKE_GENERATOR STREQUAL "Ninja")