rustc: Enable profiling support
rustc: Enable profiling support

This matches the upstream binary releases (see
https://github.com/rust-lang/rust/blob/beta/src/ci/docker/x86_64-gnu/Dockerfile).

Upstream also enables sanitizer support but that adds another 39 MiB
to the package size, and who needs sanitizers in Rust anyway ;-)

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