I have installed meld 3.14.2, at last (on NFS share in Redhat 6.3 server), after nearly 40 hours of efforts , installing each and every dependency and at last seems to be succes
Well I am unsure why you are installing it to its own prefix... but just setting GSETTINGS_SCHEMA_DIR to the full path to the schema dir should work.
GSETTINGS_SCHEMA_DIR