The culprit is configure.ac: in 0.6.1 sources it has "AM_INIT_AUTOMAKE(liblrdf, 0.5.0)", while likely it should be "AM_INIT_AUTOMAKE(liblrdf, 0.6.1)".
That causes the wrong value to be inserted in the statement "Version: @Version@" in the lrdf.pc.in file.
