[CM] Snd 21.1

[bil at ccrma.Stanford.EDU]

Snd 21.1:

s7: s7_hash_code and hash-code (like CL's sxhash)
     s7_define_semisafe_typed_function

checked: notcurses 2.1.6, sbcl 2.1.1

Thanks!: Massimiliano Gubinelli, IOhannes m zmoelnig