[CM] a short guide on compile on msys2/windows with cload.scm

[bil at ccrma.Stanford.EDU]

> Would you mind give some pointers on how to get the path of
> the s7 binary?

I don't know about msys or windows, but one thing to
look at is s7.c line 97490 or so which looks at
argv[0] when s7 runs standalone.  It uses realpath
but it isn't foolproof.

(The problems in this regard convinced me to make
nrepl completely self-contained).