stdenv: Store one package per line in nix-support/propagated-*

This makes those files a bit easier to read. Also, for what it's worth,
it brings us one baby step closer to handling spaces in store paths.

Also, I optimized handling of many transitive deps with read. Probably,
not very beneficial, but nice to enforce the pkg-per-line structure.
Doing so let me find much dubious code and fix it.

Two misc notes:

 - `propagated-user-env-packages` also needed to be adjusted as
   sometimes it is copied to/from the propagated input files.

 - `local fd` should ensure that file descriptors aren't clobbered
   during recursion.

1 files changed, 1 insertions, 1 deletions

diff --git a/pkgs/build-support/trivial-builders.nix b/pkgs/build-support/trivial-builders.nix
index 4debd9636396..1ee1fe8298fd 100644
--- a/pkgs/build-support/trivial-builders.nix
+++ b/pkgs/build-support/trivial-builders.nix
@@ -84,7 +84,7 @@ rec {
         mkdir -p $out/nix-support
         cp ${script} $out/nix-support/setup-hook
       '' + lib.optionalString (deps != []) ''
-        echo ${toString deps} > $out/nix-support/propagated-native-build-inputs
+        printLines ${toString deps} > $out/nix-support/propagated-native-build-inputs
       '' + lib.optionalString (substitutions != {}) ''
         substituteAll ${script} $out/nix-support/setup-hook
       '');