EvalState::callFunction(): Make FunctionCallTrace use less stack space

The FunctionCallTrace object consumes a few hundred bytes of stack
space, even when tracing is disabled. This was causing stack overflows:

  $ nix-instantiate '<nixpkgs> -A texlive.combined.scheme-full --dry-run
  error: stack overflow (possible infinite recursion)

This is with the default stack size of 8 MiB.

Putting the object on the heap reduces stack usage to < 5 MiB.

(cherry picked from commit 98ef11677c43db9aa669768d9f0cbec704e8831c)

0 files changed, 0 insertions, 0 deletions