[Jscheme-devel] string.scm from MIT Scheme 7.7.1

[Geoffrey K. <ge...@kn...>]

I needed some string handling functions, so I looked at MIT Scheme's 
src/runtime/string.scm, cannibalized what I needed, and it worked fine 
in JScheme.  I had to change "fix:" arithmetic function calls to 
ordinary ones, and decide if I wanted to adopt `guarantee-string'.