Temporarily disable the debugger during completion evaluation
Temporarily disable the debugger during completion evaluation

readline is not re-entrant, so entering the debugger from the
completioncallback results in an eventual segfault.

The workaround is to temporarily disable the debugger when searching
for possible completions.

NixOS/nix,NixOS/nix,NixOS/nix,NixOS/nix,NixOS/nix