rust: use pkgsBuildHost/pkgsTargetTarget

We're already using pkgsBuildBuild, and we'll soon be using
pkgsBuildTarget, so for consistency, change buildPackages and
targetPackages to their corresponding two-component names.

pkgs/build-support/rust/lib/default.nix

···
 { lib
 , stdenv
-, buildPackages
-, targetPackages
+, pkgsBuildHost
+, pkgsTargetTarget
 }:
 
 rec {
···
     # As a workaround for https://github.com/rust-lang/rust/issues/89626 use lld on pkgsStatic aarch64
     shouldUseLLD = platform: platform.isAarch64 && platform.isStatic && !stdenv.isDarwin;
 
-    ccForBuild = "${buildPackages.stdenv.cc}/bin/${buildPackages.stdenv.cc.targetPrefix}cc";
-    cxxForBuild = "${buildPackages.stdenv.cc}/bin/${buildPackages.stdenv.cc.targetPrefix}c++";
+    ccForBuild = "${pkgsBuildHost.stdenv.cc}/bin/${pkgsBuildHost.stdenv.cc.targetPrefix}cc";
+    cxxForBuild = "${pkgsBuildHost.stdenv.cc}/bin/${pkgsBuildHost.stdenv.cc.targetPrefix}c++";
     linkerForBuild = ccForBuild;
 
     ccForHost = "${stdenv.cc}/bin/${stdenv.cc.targetPrefix}cc";
     cxxForHost = "${stdenv.cc}/bin/${stdenv.cc.targetPrefix}c++";
     linkerForHost = if shouldUseLLD stdenv.targetPlatform
       && !stdenv.cc.bintools.isLLVM
-      then "${buildPackages.lld}/bin/ld.lld"
+      then "${pkgsBuildHost.lld}/bin/ld.lld"
       else ccForHost;
 
-    # Unfortunately we must use the dangerous `targetPackages` here
+    # Unfortunately we must use the dangerous `pkgsTargetTarget` here
     # because hooks are artificially phase-shifted one slot earlier
     # (they go in nativeBuildInputs, so the hostPlatform looks like
     # a targetPlatform to them).
-    ccForTarget = "${targetPackages.stdenv.cc}/bin/${targetPackages.stdenv.cc.targetPrefix}cc";
-    cxxForTarget = "${targetPackages.stdenv.cc}/bin/${targetPackages.stdenv.cc.targetPrefix}c++";
-    linkerForTarget = if shouldUseLLD targetPackages.stdenv.targetPlatform
-      && !targetPackages.stdenv.cc.bintools.isLLVM # whether stdenv's linker is lld already
-      then "${buildPackages.lld}/bin/ld.lld"
+    ccForTarget = "${pkgsTargetTarget.stdenv.cc}/bin/${pkgsTargetTarget.stdenv.cc.targetPrefix}cc";
+    cxxForTarget = "${pkgsTargetTarget.stdenv.cc}/bin/${pkgsTargetTarget.stdenv.cc.targetPrefix}c++";
+    linkerForTarget = if shouldUseLLD pkgsTargetTarget.stdenv.targetPlatform
+      && !pkgsTargetTarget.stdenv.cc.bintools.isLLVM # whether stdenv's linker is lld already
+      then "${pkgsBuildHost.lld}/bin/ld.lld"
       else ccForTarget;
 
     rustBuildPlatform = stdenv.buildPlatform.rust.rustcTarget;
···
     setEnv = ''
     env \
     ''
-    # Due to a bug in how splicing and targetPackages works, in
-    # situations where targetPackages is irrelevant
-    # targetPackages.stdenv.cc is often simply wrong.  We must omit
+    # Due to a bug in how splicing and pkgsTargetTarget works, in
+    # situations where pkgsTargetTarget is irrelevant
+    # pkgsTargetTarget.stdenv.cc is often simply wrong.  We must omit
     # the following lines when rustTargetPlatform collides with
     # rustHostPlatform.
     + lib.optionalString (rustTargetPlatform != rustHostPlatform) ''
···
       "CXX_${stdenv.buildPlatform.rust.cargoEnvVarTarget}=${cxxForBuild}" \
       "CARGO_TARGET_${stdenv.buildPlatform.rust.cargoEnvVarTarget}_LINKER=${linkerForBuild}" \
       "CARGO_BUILD_TARGET=${rustBuildPlatform}" \
-      "HOST_CC=${buildPackages.stdenv.cc}/bin/cc" \
-      "HOST_CXX=${buildPackages.stdenv.cc}/bin/c++" \
+      "HOST_CC=${pkgsBuildHost.stdenv.cc}/bin/cc" \
+      "HOST_CXX=${pkgsBuildHost.stdenv.cc}/bin/c++" \
     '';
   };
 } // lib.mapAttrs (old: new: platform:

pkgs/development/compilers/rust/1_75.nix

···
 # 3. Firefox and Thunderbird should still build on x86_64-linux.
 
 { stdenv, lib
-, buildPackages
-, targetPackages
 , newScope, callPackage
 , CoreFoundation, Security, SystemConfiguration
-, pkgsBuildTarget, pkgsBuildBuild, pkgsBuildHost
+, pkgsBuildTarget, pkgsBuildBuild, pkgsBuildHost, pkgsTargetTarget
 , makeRustPlatform
 , wrapRustcWith
 , llvmPackages_17, llvm_17
···
   rustcPatches = [ ];
 }
 
-(builtins.removeAttrs args [ "pkgsBuildTarget" "pkgsBuildHost" "llvmPackages_17" "llvm_17"])
+(builtins.removeAttrs args [ "pkgsBuildTarget" "llvmPackages_17" "llvm_17"])

pkgs/development/compilers/rust/default.nix

···
 , llvmPackages # Exposed through rustc for LTO in Firefox
 }:
 { stdenv, lib
-, buildPackages
-, targetPackages
 , newScope, callPackage
 , CoreFoundation, Security, SystemConfiguration
 , pkgsBuildBuild
+, pkgsBuildHost
+, pkgsTargetTarget
 , makeRustPlatform
 , wrapRustcWith
 }:
 
 let
   # Use `import` to make sure no packages sneak in here.
-  lib' = import ../../../build-support/rust/lib { inherit lib stdenv buildPackages targetPackages; };
+  lib' = import ../../../build-support/rust/lib { inherit lib stdenv pkgsBuildHost pkgsTargetTarget; };
   # Allow faster cross compiler generation by reusing Build artifacts
   fastCross = (stdenv.buildPlatform == stdenv.hostPlatform) && (stdenv.hostPlatform != stdenv.targetPlatform);
 in
···
       else
         self.buildRustPackages.overrideScope (_: _:
         lib.optionalAttrs (stdenv.buildPlatform == stdenv.hostPlatform)
-          (selectRustPackage buildPackages).packages.prebuilt);
+          (selectRustPackage pkgsBuildHost).packages.prebuilt);
       bootRustPlatform = makeRustPlatform bootstrapRustPackages;
     in {
       # Packages suitable for build-time, e.g. `build.rs`-type stuff.
-      buildRustPackages = (selectRustPackage buildPackages).packages.stable // { __attrsFailEvaluation = true; };
+      buildRustPackages = (selectRustPackage pkgsBuildHost).packages.stable // { __attrsFailEvaluation = true; };
       # Analogous to stdenv
       rustPlatform = makeRustPlatform self.buildRustPackages;
       rustc-unwrapped = self.callPackage ./rustc.nix ({