From c74b782bcf02b00e9747c12aed7d5a400f2d4041 Mon Sep 17 00:00:00 2001
From: Karolis Stasaitis <contact@carlossless.io>
Date: Wed, 15 Jul 2026 13:05:12 +0200
Subject: [PATCH] yosys-bluespec: fix build with yosys 0.67

---
 pkgs/development/compilers/yosys/plugins/bluespec.nix | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/pkgs/development/compilers/yosys/plugins/bluespec.nix b/pkgs/development/compilers/yosys/plugins/bluespec.nix
index 4379a5a16394..84a31eb5b12f 100644
--- a/pkgs/development/compilers/yosys/plugins/bluespec.nix
+++ b/pkgs/development/compilers/yosys/plugins/bluespec.nix
@@ -21,6 +21,12 @@ stdenv.mkDerivation {
     sha256 = "sha256-3cNFP/k4JsgLyUQHWU10Htl2Rh0staAcA3R4piD6hDE=";
   };
 
+  # yosys >=0.67 headers require C++20; the Makefile otherwise pins c++17.
+  postPatch = ''
+    substituteInPlace Makefile \
+      --replace-fail '-std=c++17' '-std=c++20'
+  '';
+
   buildInputs = [
     yosys
     readline