For some reason in your build, the first bootstrap use of the compiler (to generate the sysconfig data) is failing because the runpy module can't be found.  Python should be able to find it in the source directory; the "Could not find platform dependent libraries <exec_prefix>" is normal at this point and can be ignored.  I see from your config.log that you do have a lot of configure options set, including some invalid ones (configure:16344: WARNING: unrecognized options: --enable-clocale, --enable-debug).  I suggest you try rebuilding from a freshly untarred source directory with as simple a ./configure as possible and as few environment variables set as possible and see what happens when you run make, something like:

./configure && make

If that fails similarly, please include that whole output from configure through make and the config.log output.