postgres-lsp: Use system jemalloc

pkgs/by-name/po/postgres-lsp/package.nix

@@ -2,6 +2,7 @@
   lib,
   rustPlatform,
   fetchFromGitHub,
+  rust-jemalloc-sys,
 }:
 rustPlatform.buildRustPackage (finalAttrs: {
   pname = "postgres-lsp";
@@ -22,6 +23,10 @@ rustPlatform.buildRustPackage (finalAttrs: {
     rustPlatform.bindgenHook
   ];
 
+  buildInputs = [
+    rust-jemalloc-sys
+  ];
+
   env = {
     SQLX_OFFLINE = 1;