"port install meld" does not yield working executable

[joerg van den hoff]

after "port install meld", on trying to start the program I get on the command line from which it is 
started the message

"
dbus[70231]: Dynamic session lookup supported but failed: launchd did not provide a socket path, 
verify that org.freedesktop.dbus-session.plist is loaded!

** (meld:70231): WARNING **: 18:11:03.149: Failed to load shared library 
'./gtksourceview/libgtksourceview-4.0.dylib' referenced by the typelib: 
dlopen(./gtksourceview/libgtksourceview-4.0.dylib, 9): image not found
Meld requires GtkSourceView 4.0 or higher.
"

and a small pop up window from the `meld' GUI telling "Meld requires GtkSourceView 4.0 or higher."

`port installed' lists

   gtksourceview4 @4.8.0_0+x11 (active)


I don't understand the

dbus[70231]: Dynamic session lookup supported but failed: launchd did not provide a socket path, 
verify that org.freedesktop.dbus-session.plist is loaded!

hint nor what I can do about it.

seen with 10.15.7 and current MacPorts.

any ideas?

thx/joerg