chicken -- multiple vulnerabilities

CHICKEN reports:

CVE-2017-6949: Unchecked malloc() call in SRFI-4
constructors when allocating in non-GC memory, resulting
in potential 1-word buffer overrun and/or segfault
CVE-2017-9334: “length” crashes on improper lists
CVE-2017-11343: The randomization factor of the symbol
table was set before the random seed was set, causing it
to have a fixed value on many platforms