buildDhallUrl: fix impure proxy variable passing (#178544)

PR #177891 tried fixing a problem with `buildDhallUrl` in environments
where proxy variables are necessary for internet access to work. The
`impureEnvVars` should be set in `downloadEncodedFile` instead of the
final `runCommand`, as the former is an FOD, the latter isn't.

authored by Johannes Maier and committed by GitHub 39e6ebdf 73258f34

+2 -1
+2 -1
pkgs/development/interpreters/dhall/build-dhall-url.nix
··· 59 59 outputHash = hash; 60 60 name = baseNameOf url; 61 61 nativeBuildInputs = [ cacert ]; 62 + impureEnvVars = lib.fetchers.proxyImpureEnvVars; 62 63 } 63 64 '' 64 65 echo "${url} ${dhallHash}" > in-dhall-file ··· 76 77 sourceFile = "source.dhall"; 77 78 78 79 in 79 - runCommand name { impureEnvVars = lib.fetchers.proxyImpureEnvVars; } 80 + runCommand name { } 80 81 ('' 81 82 set -eu 82 83