cargo: move cert info to fetch-cargo-tarball

As proposed in https://github.com/NixOS/nixpkgs/pull/82496, we should only set the related env vars for the fetcher instead of breaking the function of cargo itself.

pkgs/build-support/rust/fetch-cargo-tarball/default.nix

@@ -73,6 +73,9 @@ in stdenv.mkDerivation ({
 
     ${cargoUpdateHook}
 
+    # Override the `http.cainfo` option usually specified in `.cargo/config`.
+    export CARGO_HTTP_CAINFO=${cacert}/etc/ssl/certs/ca-bundle.crt
+
     cargo vendor $name --respect-source-config | cargo-vendor-normalise > $CARGO_CONFIG
 
     # Create an empty vendor directory when there is no dependency to vendor

pkgs/development/compilers/rust/cargo.nix

@@ -1,6 +1,6 @@
 { lib, stdenv, pkgsHostHost
 , file, curl, pkg-config, python3, openssl, cmake, zlib
-, installShellFiles, makeWrapper, cacert, rustPlatform, rustc
+, installShellFiles, makeWrapper, rustPlatform, rustc
 , CoreFoundation, Security
 , auditable ? false # TODO: change to true when this is the default
 }:
@@ -28,7 +28,7 @@ rustPlatform.buildRustPackage {
     (lib.getDev pkgsHostHost.curl)
     zlib
   ];
-  buildInputs = [ cacert file curl python3 openssl zlib ]
+  buildInputs = [ file curl python3 openssl zlib ]
     ++ lib.optionals stdenv.isDarwin [ CoreFoundation Security ];
 
   # cargo uses git-rs which is made for a version of libgit2 from recent master that
@@ -39,14 +39,7 @@ rustPlatform.buildRustPackage {
   RUSTC_BOOTSTRAP = 1;
 
   postInstall = ''
-    # NOTE: We override the `http.cainfo` option usually specified in
-    # `.cargo/config`. This is an issue when users want to specify
-    # their own certificate chain as environment variables take
-    # precedence
-    wrapProgram "$out/bin/cargo" \
-      --suffix PATH : "${rustc}/bin" \
-      --set CARGO_HTTP_CAINFO "${cacert}/etc/ssl/certs/ca-bundle.crt" \
-      --set SSL_CERT_FILE "${cacert}/etc/ssl/certs/ca-bundle.crt"
+    wrapProgram "$out/bin/cargo" --suffix PATH : "${rustc}/bin"
 
     installManPage src/tools/cargo/src/etc/man/*