Compare what you get downloading ECL via anonymous CVS(http://ecls.sourceforge.net/cvs.html) with what you get clicking on "Download tarball" here: http://common-lisp.net/cgi-bin/viewcvs.cgi/ecl/?root=ecl
It appears that ViewCVS can access the up-to-date sources(what Juan-Jose commits) but that anonymous CVS is stuck somewhere in the past(approximately 4 days)