Use Nix's restricted evaluation mode

Dependencies

• [2] 7GKAIP3V Fix build and handling of string inputs starting with a dash
• [*] 4N5APGRG * Start of a helper tool to evaluate job expressions efficiently.

Change contents

• edit in src/c/hydra-eval-jobs.cc at line 244
  [2.1195]

  [4.854]
  +

  + /* Prevent access to paths outside of the Nix search path and

  + to the environment. */

  + settings.set("restrict-eval", "true");