racket version of compat
add r6rs signatures
export syntax-rules for phase level 2

by defining a custom implementation language that we can use to
address issues like these in this codebase
syntax-rules at phase 2 not enough for match, provide more

actually easier to just provide everything in phase 2
in addition to phase -1, 0, and 1

just provide from 'compat', easier that way, since match
also needs some of the compat routines at phase 2

possibly now doing extra work also done by 'import'
add makefile and rule for creating symlinks for Racket

symlinks all .scm file under lib/ unless .rkt version of same
already exists

this allows require of the form elegant-weapons/blah instead of
(lib "blah.scm" "elegant-weapons")

more importantly, find-version.rkt in r6rs does not support .scm
as an extension, meaning that 'import' of the .scm files will fail,
unless we have the symlinks (could instead rename or patch Racket)

presently supported extensions are:

  #".mzscheme.ss" #".mzscheme.sls" #".ss" #".sls" #".rkt"
implement racket version of define-match as incompatibility fix

now all the modules are loading for racket
test runner rule for racket
ignore .rkt symlinks
use .rkt files consistently to perhaps avoid duplicate loading