Snd 25.8

s7: (*s7* 'scheme-version) which is 's7 by default but can
       be set to 'r5rs or 'r7rs.  The r7rs support is built-in.
       To get a repl with both the repl and r7rs stuff built-in,
       use the compiler switches WITH_R7RS and WITH_NOTCURSES.
    added s7_c_object_set_value
    added s7_defun

checked: sbcl 2.5.9

Thanks!: Jinsar Kafka, Matthew