[nix] fix infinite-recursion when importing overlay

Signed-off-by: Avimitin <[email protected]>

Author: Avimitin

flake.nix

@@ -14,6 +14,7 @@
     inputs@{
       self,
       nixpkgs,
+      nixpkgs-for-llvm,
       mill-ivy-fetcher,
       circt-follow,
       ...
@@ -52,6 +53,10 @@
               mill-ivy-fetcher.overlays.default
               # Follow CIRCT from sequencer/zaozi overlay
               circt-follow.overlays.default
+              # pin riscv32 packages to avoid consistent breakage
+              (final: prev: {
+                rv32_nixpkgs = nixpkgs-for-llvm.legacyPackages."${system}".pkgsCross.riscv32-embedded;
+              })
               overlay
             ];
           };

nix/overlay.nix

@@ -1,16 +1,11 @@
-{ self }:
-
 final: prev:
 
 let
   llvmForRVV_attrName = "llvmPackages_git";
-  rv32_pkgs =
-    self.inputs.nixpkgs-for-llvm.legacyPackages."${final.system}".pkgsCross.riscv32-embedded;
-  rv32_buildPkgs = rv32_pkgs.buildPackages;
+  rv32_pkgs = final.rv32_nixpkgs;
+  rv32_buildPkgs = final.rv32_nixpkgs.buildPackages;
 in
 rec {
-  inherit rv32_pkgs rv32_buildPkgs; # for easier inspection
-
   getEnv' =
     key:
     let