In some scenarios, configure produces a Makefile which fails because ASDLGEN doesn't point to a working Python. In particular, it seems to assume that if there is an executable called e.g. "python3.4" on the path, then that will be a system Python. In my perhaps unusual but IMO perfectly valid setup, I have various Python repos set up like so: $HOME/projects/python | +- default | +- 3.3 | + and so on for 3.2, 3.1, 2.7 In order to facilitate testing some script against multiple Python versions, I have shell scripts in $HOME/bin named python3.4, python3.3 etc. which just run the programs in the relevant directories in $HOME/projects/python/. (I know I can do this using aliases etc., but I think that's beside the point.) When I run configure in the repo for the default branch, it appears to look for a Python on the path named python3.4, finds one in $HOME/bin, and thus generates an ASDLGEN value of "python3.4". If I happen to have a built Python in the default repo, then the script in $HOME/bin will successfully run that, and all appears well; but if I clean the default repo and re-run make, it fails at the ASDLGEN step, because the $HOME/bin/python3.4 script fails, due to not being able to invoke $HOME/projects/python/default/python. Is this a bug in configure, or is my configuration regarded as too perverse to support? Regards, Vinay Sajip