Compiling webkitgtk 20.1 fails with: [ 0%] Built target WebKit-fake-api-headers [ 1%] Built target bmalloc [ 10%] Built target WTFForwardingHeaders [ 22%] Built target WTF [ 23%] Built target stageSharedScripts [ 23%] Built target LLIntOffsetsExtractor [ 39%] Built target JavaScriptCoreForwardingHeaders [ 46%] Built target JavaScriptCore [ 47%] Built target xdgmime [ 47%] Built target PAL [ 50%] Built target ANGLESupport [ 50%] Generate bindings (WebCoreBindings) [ 50%] Built target WebCoreBindings [ 50%] Building CXX object Source/WebCore/CMakeFiles/WebCore.dir/Modules/quota/NavigatorStorageQuota.cpp.o /src/gnome/webkitgtk-2.20.1/Source/WebCore/Modules/quota/NavigatorStorageQuota.cpp: In static member function ‘static WebCore::NavigatorStorageQuota* WebCore::NavigatorStorageQuota::from(WebCore::Navigator*)’: /src/gnome/webkitgtk-2.20.1/Source/WebCore/Modules/quota/NavigatorStorageQuota.cpp:58:70: error: ‘window’ was not declared in this scope auto newSupplement = std::make_unique<NavigatorStorageQuota>(window); ^~~~~~ /src/gnome/webkitgtk-2.20.1/Source/WebCore/Modules/quota/NavigatorStorageQuota.cpp:58:70: note: suggested alternative: ‘sincos’ auto newSupplement = std::make_unique<NavigatorStorageQuota>(window); ^~~~~~ sincos make[2]: *** [Source/WebCore/CMakeFiles/WebCore.dir/build.make:2609: Source/WebCore/CMakeFiles/WebCore.dir/Modules/quota/NavigatorStorageQuota.cpp.o] Error 1 make[1]: *** [CMakeFiles/Makefile2:772: Source/WebCore/CMakeFiles/WebCore.dir/all] Error 2 make: *** [Makefile:152: all] Error 2