Relocatable bison candidate solution

Attempt at fixing the ability to move bison to CVMFS. Related to failing gcc8 opt/debug builds, e.g. https://cdash.cern.ch/viewFiles.php?buildid=777477

The fix should prevent bison from keeping invalid paths internally, allowing it to be moved around in the directory tree. Proposed solution is based on https://www.gnu.org/software/bison/manual/bison.html section 12.7.