treewide: replace make/build/configure/patchFlags with nix lists

pkgs/development/ruby-modules/gem-config/default.nix

@@ -236,7 +236,7 @@ in
     nativeBuildInputs = [ pkgconfig ];
     buildInputs = [ openssl ];
     hardeningDisable = [ "format" ];
-    NIX_CFLAGS_COMPILE = [
+    NIX_CFLAGS_COMPILE = toString [
       "-Wno-error=stringop-overflow"
       "-Wno-error=implicit-fallthrough"
       "-Wno-error=sizeof-pointer-memaccess"
@@ -495,23 +495,22 @@ in
   sassc = attrs: {
     nativeBuildInputs = [ rake ];
     dontBuild = false;
-    SASS_LIBSASS_PATH = libsass;
+    SASS_LIBSASS_PATH = toString libsass;
     postPatch = ''
       substituteInPlace lib/sassc/native.rb \
         --replace 'gem_root = spec.gem_dir' 'gem_root = File.join(__dir__, "../../")'
     '';
-  } // (if stdenv.isDarwin then {
+  } // (lib.optionalAttrs stdenv.isDarwin {
     # https://github.com/NixOS/nixpkgs/issues/19098
-    buildFlags = "--disable-lto";
-  } else {});
+    buildFlags = [ "--disable-lto" ];
+  });
 
-  scrypt = attrs:
-    if stdenv.isDarwin then {
-      dontBuild = false;
-      postPatch = ''
-        sed -i -e "s/-arch i386//" Rakefile ext/scrypt/Rakefile
-      '';
-    } else {};
+  scrypt = attrs: lib.optionalAttrs stdenv.isDarwin {
+    dontBuild = false;
+    postPatch = ''
+      sed -i -e "s/-arch i386//" Rakefile ext/scrypt/Rakefile
+    '';
+  };
 
   semian = attrs: {
     buildInputs = [ openssl ];