dsniff: unbreak the build
dsniff: unbreak the build

We revert to using GCC 9 for compilation, in order to work around a GCC 10 bug
resulting in a segfault when compiling.

The alternative would be to restrict to optimization level -O1, but this
disables fortify.

NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs