diff -u -r webkitgtk-2.20.2/Source/PlatformGTK.cmake webkitgtk-2.20.2-doc/Source/PlatformGTK.cmake
--- webkitgtk-2.20.2/Source/PlatformGTK.cmake	2018-05-07 10:30:18.000000000 +0200
+++ webkitgtk-2.20.2-doc/Source/PlatformGTK.cmake	2018-05-07 18:03:44.333500803 +0200
@@ -15,10 +15,10 @@
 
 if (ENABLE_GTKDOC)
     install(DIRECTORY ${CMAKE_BINARY_DIR}/Documentation/webkit2gtk-${WEBKITGTK_API_VERSION}/html/webkit2gtk-${WEBKITGTK_API_VERSION}
-            DESTINATION "${CMAKE_INSTALL_DATADIR}/gtk-doc/html/webkit2gtk-${WEBKITGTK_API_VERSION}"
+            DESTINATION "${CMAKE_INSTALL_DATADIR}/gtk-doc/html"
     )
     install(DIRECTORY ${CMAKE_BINARY_DIR}/Documentation/webkitdomgtk-${WEBKITGTK_API_VERSION}/html/webkitdomgtk-${WEBKITGTK_API_VERSION}
-            DESTINATION "${CMAKE_INSTALL_DATADIR}/gtk-doc/html/webkitdomgtk-${WEBKITGTK_API_VERSION}"
+            DESTINATION "${CMAKE_INSTALL_DATADIR}/gtk-doc/html"
     )
 endif ()