mod-inverse returns incorrect answer

[Takashi Kato]

This should return 84793287459004005994083570264676611930995373170935977255695558296701128546491 but -1868565590369779796042771496011207097362409954010577056616565239046619145529369611450115909.

(mod-inverse
  59791678501913488631701617161572303141620876383029885416585973023996318696896
  115792089210356248762697446949407573530086143415290314195533631308867097853951)

NB: this only happens 32 bit environment. More precisely 32bit long environment.

[Takashi Kato]

Fixed value

[Takashi Kato]

Clearing stack area. Fixes #208)

→ <<cset 0dfedd405853>>