[CM] S7 questions and libc issue

[bil at ccrma.Stanford.EDU]

> ;unbound variable (symbol "\x7f;ELF\x02;\x01;\x01;")

This happens if you try to dynamically load an object file
but don't have the dynamic loading functions -- when you
build it without libdl (WITH_C_LOADER=0 probably).  It treats
libc_s7.so as a scheme (text) file.

r7rs.scm needs the libc stuff; it starts with (require libc.scm).
I suppose you could make a separate C program that loads s7.o
and libc_s7.so.  There is no way to do this with just s7.c itself.
There are examples in s7.html of how to do this sort of thing.
Also r7rs.scm is not a full r7rs implementation, and I have no
plans to make it one.