don't recognize type dependency as fulfilled when type plugin is in source...

don't recognize type dependency as fulfilled when type plugin is in source tree but not built (e.g. type plugin misses dependencies) (Thanks to Matthias Moeller for the Patch)

cmake/plugin.cmake

@@ -329,7 +329,7 @@ macro (_check_plugin_deps _prefix _optional )
       if  ( DEFINED ${_prefix}_TYPES )
 
           foreach (_TYPE ${${_prefix}_TYPES})
-             if ( DEFINED ${_TYPE}_INCLUDE )
+             if ( TARGET ${_TYPE} )
                list(APPEND ${_prefix}_TYPE_INCLUDES "${${_TYPE}_INCLUDE}")
                list(APPEND ${_prefix}_TYPE_DEPENDENCIES "${_TYPE}")
                list(APPEND ${_prefix}_TYPE_DEFINITIONS "-DENABLE_${_TYPE}_SUPPORT")
@@ -348,12 +348,12 @@ macro (_check_plugin_deps _prefix _optional )
 
           foreach (_TYPE ${${_prefix}_OPT_TYPES})
 
-             if ( DEFINED ${_TYPE}_INCLUDE )
+             if ( TARGET ${_TYPE} )
                list(APPEND ${_prefix}_TYPE_INCLUDES "${${_TYPE}_INCLUDE}")
                list(APPEND ${_prefix}_TYPE_DEPENDENCIES "${_TYPE}")
                list(APPEND ${_prefix}_TYPE_DEFINITIONS "-DENABLE_${_TYPE}_SUPPORT")
              else()
-               message(warning "Optional Datatype ${_TYPE} not available, proceeding without it")
+               message("Optional Datatype ${_TYPE} not available, proceeding without it")
              endif()
 
           endforeach()