matrix-tuwunel: drop reference to rustc (#462712)

pkgs/by-name/ma/matrix-tuwunel/dont-record-compilation-flags.patch

@@ -0,0 +1,21 @@
+commit be2b9e1992f5a7048fe011f4d48591dfcec927a8
+Author: Guillaume Girol <symphorien+git@xlumurb.eu>
+Date:   Mon Nov 17 12:00:00 2025 +0000
+
+    make the macro recording conpilation flags a noop
+    
+    it records references to rustc which increases the size of the closure of tuwunel by 1.5 GB.
+
+diff --git a/src/macros/mod.rs b/src/macros/mod.rs
+index b5c5b67d..86f4755b 100644
+--- a/src/macros/mod.rs
++++ b/src/macros/mod.rs
+@@ -39,7 +39,7 @@ pub fn recursion_depth(args: TokenStream, input: TokenStream) -> TokenStream {
+ }
+ 
+ #[proc_macro]
+-pub fn rustc_flags_capture(args: TokenStream) -> TokenStream { rustc::flags_capture(args) }
++pub fn rustc_flags_capture(_args: TokenStream) -> TokenStream { TokenStream::default() }
+ 
+ #[proc_macro]
+ pub fn rustc_version(args: TokenStream) -> TokenStream { rustc::version(args) }

pkgs/by-name/ma/matrix-tuwunel/package.nix

@@ -19,6 +19,7 @@
   liburing,
   nixosTests,
   writeTextFile,
+  rustc-unwrapped,
 }:
 let
   rust-jemalloc-sys' = rust-jemalloc-sys.override {
@@ -103,6 +104,12 @@ rustPlatform.buildRustPackage (finalAttrs: {
     rustPlatform.bindgenHook
   ];
 
+  patches = [
+    # reduce closure size by not storing a reference to rustc-unwrapped
+    # alternative to https://github.com/NixOS/nixpkgs/pull/462394
+    ./dont-record-compilation-flags.patch
+  ];
+
   buildInputs = [
     bzip2
     zstd
@@ -172,6 +179,8 @@ rustPlatform.buildRustPackage (finalAttrs: {
     };
   };
 
+  disallowedReferences = [ rustc-unwrapped ];
+
   meta = {
     description = "Matrix homeserver written in Rust, official successor to conduwuit";
     homepage = "https://github.com/matrix-construct/tuwunel";