repeat of NixOS#144825, part of NixOS#346453, should be 0 rebuilds

Madie using

```
export NIXPKGS_ALLOW_UNFREE=1
export NIXPKGS_ALLOW_INSECURE=1
export NIXPKGS_ALLOW_BROKEN=1

git reset
git restore .

nix eval -f pkgs/build-support/fetchurl/mirrors.nix --json |
    jq '
        to_entries[]
            | .key as $key
            | .value[]
            | @sh "rg \(.) -l pkgs/ -tnix | xe sd \(.) mirror://\($key)/"
        ' -r |
    bash -x

git restore -- pkgs/build-support/fetchurl/mirrors.nix
git restore -- pkgs/applications/networking/browsers/
git restore -- pkgs/development/haskell-modules/

test -s packages.json || ( set -x;
    time nix-env --extra-experimental-features no-url-literals --option system x86_64-linux -f ./. -qaP --json --meta --show-trace --no-allow-import-from-derivation > packages.json
)

MODIFIED="$(git ls-files --modified)"

jq <packages.json 'to_entries[] | select(.value.meta.position==null|not) | "\(.key)\t\(.value.meta.position)"' -r |
    sed -e "s#\t$(realpath .)/#\t#" |
    sed -e 's#:\([0-9]*\)$#\t\1#' |
    grep --fixed-strings "$MODIFIED" |
    while read attrpath position col; do
        if test -z $(git diff -- "$position"); then
            continue
        fi
        if nix-build . -A "$attrpath".src \
        && nix-build . -A "$attrpath".src --check \
        && nix-build . -A "$attrpath".patches \
        && nix-build . -A "$attrpath".patches --check
        then
            git add -- "$position"
        else
            git reset -- "$position"
            git restore -- "$position"
        fi
    done
```

Then I verified the FOD hashes for each `--patch` i accepted.

FOD hash verification:

```
$ nix-prefetch-url $(nix eval -f default.nix activemq.src.url --raw | tee >( cat >&2; echo >&2 )) | xargs nix hash to-sri --type sha256
mirror://apache/activemq/6.1.5/apache-activemq-6.1.5-bin.tar.gz
path is '/nix/store/gmh0hzsglbfyrcqkjiyf0kvwcyqqgz5p-apache-activemq-6.1.5-bin.tar.gz'
sha256-JrLLSm6+Be1vSBTTryRcZfbiGK0PrmJ/pM2uYnGuN9E=

$ nix-prefetch-url $(nix eval -f default.nix libxmlxx5.src.url --raw | tee >( cat >&2; echo >&2 )) | xargs nix hash to-sri --type sha256
mirror://gnome/sources/libxml++/5.4/libxml++-5.4.0.tar.xz
path is '/nix/store/8zy5makss1dcijprf5bilz5qqz59xg2p-libxml++-5.4.0.tar.xz'
sha256-6aI8Q2aGqUaY0hOOa8uvhJEh1jv6D1DcNP77/XlWaEg=
```