added note to changelog regarding Qt version 5.7 and 5.8 problems on osx

and windows.

Documentation/DeveloperHelpSources/changelog.docu

@@ -18,7 +18,8 @@
             - Moved Icon into Plugin
      - <b>Build System</b>
          - Improved Branding support
-         - Support for Qt up to 5.9
+         - Support for Qt up to 5.9 (Using an lts version 5.9 or 5.6 is recommended)
+         - Warn if problematic Qt version is used (5.7 and 5.8 may cause GLErrors on OSX 5.8 overrides moc flags on windows. see https://bugreports.qt.io/browse/QTBUG-58345)
          - Support for VS 2017
          - Enable C++-11 by default
          - Drop support for Qt 4