python3Packages.hoomd-blue: fix cmakeFlags for __structuredAttrs

pkgs/development/python-modules/hoomd-blue/default.nix

@@ -49,13 +49,9 @@ buildPythonPackage rec {
     "-DBUILD_HPMC=${onOffBool components.hpmc}"
     "-DBUILD_MD=${onOffBool components.md}"
     "-DBUILD_METAL=${onOffBool components.metal}"
+    "-DCMAKE_INSTALL_PREFIX=${placeholder "out"}/${python.sitePackages}"
   ];
 
-  preConfigure = ''
-    # Since we can't expand $out in `cmakeFlags`
-    cmakeFlags="$cmakeFlags -DCMAKE_INSTALL_PREFIX=$out/${python.sitePackages}"
-  '';
-
   # tests fail but have tested that package runs properly
   doCheck = false;
   checkTarget = "test";