diff --git a/pkgs/by-name/un/unicorn/package.nix b/pkgs/by-name/un/unicorn/package.nix
index 54d524e33ff8..156ca182d110 100644
--- a/pkgs/by-name/un/unicorn/package.nix
+++ b/pkgs/by-name/un/unicorn/package.nix
@@ -26,8 +26,10 @@ stdenv.mkDerivation (finalAttrs: {
     cctools
   ];
 
-  # Ensure the linker is using atomic when compiling for RISC-V, otherwise fails
-  NIX_LDFLAGS = lib.optionalString stdenv.hostPlatform.isRiscV "-latomic";
+  env = lib.optionalAttrs stdenv.hostPlatform.isRiscV {
+    # Ensure the linker is using atomic when compiling for RISC-V, otherwise fails
+    NIX_LDFLAGS = "-latomic";
+  };
 
   cmakeFlags = lib.optionals (stdenv.hostPlatform.isDarwin && stdenv.hostPlatform.isAarch64) [
     # Some x86 tests are interrupted by signal 10