Fix list->string bugs.

Signed-off-by: Casey Dwyer <caseydwyer@gmail.com>
Return eof from read-char.

Signed-off-by: Casey Dwyer <caseydwyer@gmail.com>
Use const char * for li_string and li_symbol.

Signed-off-by: Casey Dwyer <caseydwyer@gmail.com>
Add p_environ.

Signed-off-by: Casey Dwyer <caseydwyer@gmail.com>
Add p_setenv.

Signed-off-by: Casey Dwyer <caseydwyer@gmail.com>
Fix ambiguous results in li_error.

Signed-off-by: Casey Dwyer <caseydwyer@gmail.com>
Match characters in li_is_eqv.

Signed-off-by: Casey Dwyer <caseydwyer@gmail.com>