GAST provides a compatibility layer between the AST
(Abstract Syntax Tree) of various Python versions, as produced by
ast.parse from the standard ast module.

NOTE: Unable to support newer versions than 0.5.5 due to breaking
python/python3-pythran. python3-pythran cannot be updated further due
to breaking academic/python3-scipy, which can't be updated due to an
older Python in Slackware 15.0.
