--- /dev/null
+diff --git a/CMakeLists.txt b/CMakeLists.txt
+index 79b1feb..259d474 100644
+--- a/CMakeLists.txt
++++ b/CMakeLists.txt
+@@ -284,16 +284,18 @@ else()
+ endif()
+
+ #SHARE - use the default on Apple as TAG_VERSION is empty
+-if(WIN32 OR OS2)
+- set(DOCDIR "${CMAKE_INSTALL_DATAROOTDIR}/doc/")
+-else()
+- if(TAG_VERSION OR BUILD_OSX_BUNDLE)
+- set(DOCDIR "${CMAKE_INSTALL_DATAROOTDIR}/doc/${MAIN_DIR_NAME}${TAG_VERSION}/")
++if(NOT DOCDIR)
++ if(WIN32 OR OS2)
++ set(DOCDIR "${CMAKE_INSTALL_DATAROOTDIR}/doc/")
+ else()
+- if(NOT WANT_VERSIONING)
+- set(DOCDIR "${CMAKE_INSTALL_DATAROOTDIR}/doc/${MAIN_DIR_NAME}/")
++ if(TAG_VERSION OR BUILD_OSX_BUNDLE)
++ set(DOCDIR "${CMAKE_INSTALL_DATAROOTDIR}/doc/${MAIN_DIR_NAME}${TAG_VERSION}/")
+ else()
+- set(DOCDIR "${CMAKE_INSTALL_DATAROOTDIR}/doc/${MAIN_DIR_NAME}-${VERSION}/")
++ if(NOT WANT_VERSIONING)
++ set(DOCDIR "${CMAKE_INSTALL_DATAROOTDIR}/doc/${MAIN_DIR_NAME}/")
++ else()
++ set(DOCDIR "${CMAKE_INSTALL_DATAROOTDIR}/doc/${MAIN_DIR_NAME}-${VERSION}/")
++ endif()
+ endif()
+ endif()
+ endif()