test makefile for a couple types of errors, comments, and the .POSIX extension; add state machine diagram for assignment RHS (work in progress)
start to add verification tokens; integrate with run_tests
add many, many more tests around backslashes in weird places
start to add verification (work in progress)
start to add verification (work in progress)
add note that this test only valid for GNU Make > 3.81
working top level makefile parser! (for a small subset definition of "working"); go down blind alley trying to handle all the evil permutations of backslash (need to start tokenizing line-by-line before char-by-char)