Thanks for the answer Roxana.
Ref. the version, actually I mean the revision number in the SVN source tree, 1260 being the latest. The 2.1.2 release may well be based on this or an earlier SVN revision, I'm going to check the "svn log" to see if says so. In any case, my main assumption is that the latest SVN is the way to go, though I may go for an early revision in order to solve this opencl problem, because I did install beagle some years ago and didn't get this problem.
Seeing as the --without-opencl option isn't working for me, I'm going to try and get opencl working first, though I only have recourse to the nvidia version. I'm hoping it might work there. I'll post further on my progress.