Although the previously-applied fix worked for its platform,
it doesn’t suffice in general.
* src/bytecode.c (exec_byte_code): Save VECTOR into stack slot
so that it survives GC. The stack slot was otherwise unused,
so this doesn’t cost us memory, only a store insn.
* src/eval.c (Ffuncall): Do not make FUN volatile, reverting
2018-10-14T19:12:04Z!gazally@runbox.com. Adding ‘volatile’
does not suffice, since storage for a volatile local can be
reclaimed after its last access (e.g., by tail recursion
elimination), which would make VECTOR invisible to GC.