Remove __clone test (not reason it should error)
Port use statement
Drop dead code
Port function/const use
Port constant declaration
Partial NS port (semicolon, no errors)
Port top level stmt

Problem: namespace\foo no longer works :/
Fix namespace\, maybe
Code cleanup
Discard NS doc comments
Add NS error checks

Those can probably be implemented in a better way now...
__halt_compiler() without haling compiler
Handle __halt_compiler()
Implement declare()
Dead code
Remove declare_stack