[CM] S7 questions and libc issue

[bil at ccrma.Stanford.EDU]

> gcc s7.c -o repl -DWITH_MAIN -I. -O2 -g -ldl -lm -Wl,-export-dynamic 
> -Wno-stringop-overflow
> fernando at linux:~/Builds/S7-scheme/s7> ./s7 r7rs.scm

You built the program "repl", then ran "s7".  Try running repl.