Conflicts: spec/tags/20/library/actor/trap_exit_tags.txt vm/exception.cpp vm/external_libs/winpthreads/src/semaphore.c
Starting with 1.9, MRI added a parser state struct like we had in Melbourne and accesses the previous global variables through macros. We had macros for some of the variables but the access was ad hoc and inconsistent. This cleanup attempts to make the access consistent. However, there are some variables like 'enc' that are still accessed via directly parser_state->.