Problem

We would like to ensure that clingo is able to bootstrap from a python 2.6-only, C++11-only environment in #20159.

Solution

• Add multiple patches which will allow python 2.6 to be built even with ~ssl and ~dbm.
• Modify the libtirpc transitive dependency so that its headers are visible to python (this is necessary to make the build pass).
• Pass --no-user-cfg only if the python version is >2.6.

Result

• These modifications to the python package allow it to be built within spack (tested on CentOS 6 with the x86 architecture).
• This makes it easier to test python 2.6 compatibility in arbitrary environments.

TODO

• This should be added to spack CI. I'm not 100% sure how to do that yet, but I think that basing this on top of bootstrapping: bootstrap spack dependencies (executable and python module) #20207 might be a way to get started on it.