rustc-demangle: replace patch with Cargo.lock

https://github.com/NixOS/nixpkgs/pull/217084 plans to migrate Rust packages to use `importCargoLock`, but the migration script cannot handle `cargoPatches`: https://github.com/NixOS/nixpkgs/pull/217084#discussion_r1111253151

pkgs/development/libraries/rustc-demangle/Cargo.lock

···
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "arbitrary"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "237430fd6ed3740afe94eefcc278ae21e050285be882804e0d6e8695f0c94691"
+
+[[package]]
+name = "cc"
+version = "1.0.69"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e70cc2f62c6ce1868963827bd677764c62d07c3d9a3e1fb1177ee1a9ab199eb2"
+
+[[package]]
+name = "compiler_builtins"
+version = "0.1.49"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "20b1438ef42c655665a8ab2c1c6d605a305f031d38d9be689ddfef41a20f3aa2"
+
+[[package]]
+name = "libfuzzer-sys"
+version = "0.4.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "36a9a84a6e8b55dfefb04235e55edb2b9a2a18488fcae777a6bdaa6f06f1deb3"
+dependencies = [
+ "arbitrary",
+ "cc",
+ "once_cell",
+]
+
+[[package]]
+name = "once_cell"
+version = "1.8.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "692fcb63b64b1758029e0a96ee63e049ce8c5948587f2f7208df04625e5f6b56"
+
+[[package]]
+name = "rustc-demangle"
+version = "0.1.20"
+dependencies = [
+ "compiler_builtins",
+ "rustc-std-workspace-core",
+]
+
+[[package]]
+name = "rustc-demangle-capi"
+version = "0.1.0"
+dependencies = [
+ "rustc-demangle",
+]
+
+[[package]]
+name = "rustc-demangle-fuzz"
+version = "0.0.0"
+dependencies = [
+ "libfuzzer-sys",
+ "rustc-demangle",
+]
+
+[[package]]
+name = "rustc-std-workspace-core"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1956f5517128a2b6f23ab2dadf1a976f4f5b27962e7724c2bf3d45e539ec098c"

pkgs/development/libraries/rustc-demangle/add-Cargo.lock.patch

···
-diff --git a/Cargo.lock b/Cargo.lock
-new file mode 100644
-index 0000000..0268b3b
---- /dev/null
-+++ b/Cargo.lock
-@@ -0,0 +1,67 @@
-+# This file is automatically @generated by Cargo.
-+# It is not intended for manual editing.
-+version = 3
-+
-+[[package]]
-+name = "arbitrary"
-+version = "1.0.1"
-+source = "registry+https://github.com/rust-lang/crates.io-index"
-+checksum = "237430fd6ed3740afe94eefcc278ae21e050285be882804e0d6e8695f0c94691"
-+
-+[[package]]
-+name = "cc"
-+version = "1.0.69"
-+source = "registry+https://github.com/rust-lang/crates.io-index"
-+checksum = "e70cc2f62c6ce1868963827bd677764c62d07c3d9a3e1fb1177ee1a9ab199eb2"
-+
-+[[package]]
-+name = "compiler_builtins"
-+version = "0.1.49"
-+source = "registry+https://github.com/rust-lang/crates.io-index"
-+checksum = "20b1438ef42c655665a8ab2c1c6d605a305f031d38d9be689ddfef41a20f3aa2"
-+
-+[[package]]
-+name = "libfuzzer-sys"
-+version = "0.4.2"
-+source = "registry+https://github.com/rust-lang/crates.io-index"
-+checksum = "36a9a84a6e8b55dfefb04235e55edb2b9a2a18488fcae777a6bdaa6f06f1deb3"
-+dependencies = [
-+ "arbitrary",
-+ "cc",
-+ "once_cell",
-+]
-+
-+[[package]]
-+name = "once_cell"
-+version = "1.8.0"
-+source = "registry+https://github.com/rust-lang/crates.io-index"
-+checksum = "692fcb63b64b1758029e0a96ee63e049ce8c5948587f2f7208df04625e5f6b56"
-+
-+[[package]]
-+name = "rustc-demangle"
-+version = "0.1.20"
-+dependencies = [
-+ "compiler_builtins",
-+ "rustc-std-workspace-core",
-+]
-+
-+[[package]]
-+name = "rustc-demangle-capi"
-+version = "0.1.0"
-+dependencies = [
-+ "rustc-demangle",
-+]
-+
-+[[package]]
-+name = "rustc-demangle-fuzz"
-+version = "0.0.0"
-+dependencies = [
-+ "libfuzzer-sys",
-+ "rustc-demangle",
-+]
-+
-+[[package]]
-+name = "rustc-std-workspace-core"
-+version = "1.0.0"
-+source = "registry+https://github.com/rust-lang/crates.io-index"
-+checksum = "1956f5517128a2b6f23ab2dadf1a976f4f5b27962e7724c2bf3d45e539ec098c"

pkgs/development/libraries/rustc-demangle/default.nix

···
     sha256 = "sha256-elxclyuLmr3N66s+pR4/6OU98k1oXI2wKVJtzWPY8FI=";
   };
 
-  cargoPatches = [
+  cargoLock = {
     # generated using `cargo generate-lockfile` since repo is missing lockfile
-    ./add-Cargo.lock.patch
-  ];
-  cargoSha256 = "sha256-1tW5TOap5MstxTXAFij3IB8TIpI+FryEX9TXlVXjRl4=";
+    lockFile = ./Cargo.lock;
+  };
+
   cargoBuildFlags = [ "-p" "rustc-demangle-capi" ];
+
+  postPatch = ''
+    ln -s ${./Cargo.lock} Cargo.lock
+  '';
+
   postInstall = ''
     mkdir -p $out/lib
     cp target/${rust.toRustTargetSpec stdenv.hostPlatform}/release/librustc_demangle.so $out/lib