Fix case typo: Box-read-reference -> Box-Read-reference.
Fix gcc debug flag and prepend ./ to exectutable path.
Fix case typo: Free-environment -> Free-Environment.
Fix case of *tests-to-skip*.
Uppercase symbols before converting to Cname (as in chap6f).
Use the ~S directive instead of ~A when emitting SCM_DefineString.

The ~S directive takes care of adding quotes and, more importantly,
escaping newlines. Apparently, strict ANSI C does not allow newlines in
string literals, and this was causing a compile error when attempting to
compile the following string with embedded newline:

"*** *** *** *** *** *** * Attention * *** *** *** ** ***
The following test forces a continuation to return multiply."