From 7d88dc9151d2aeabb4b5c8cdf41abcdecfb984ab Mon Sep 17 00:00:00 2001
From: Gaetan Lepage <gaetan@glepage.com>
Date: Sat, 7 Mar 2026 12:41:48 +0000
Subject: [PATCH] protobuf_25: fix GCC 15 compatibility

Tracking: https://github.com/NixOS/nixpkgs/issues/475479
---
 pkgs/development/libraries/protobuf/generic.nix | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/pkgs/development/libraries/protobuf/generic.nix b/pkgs/development/libraries/protobuf/generic.nix
index 3488b63b1cf2..75e7b2dc660a 100644
--- a/pkgs/development/libraries/protobuf/generic.nix
+++ b/pkgs/development/libraries/protobuf/generic.nix
@@ -85,6 +85,10 @@ stdenv.mkDerivation (finalAttrs: {
         --replace-fail \
           '#define UPB_LINKARR_SENTINEL UPB_RETAIN __attribute__((weak, used))' \
           '#define UPB_LINKARR_SENTINEL            __attribute__((weak, used))'
+    ''
+    # Fix gcc15 build failures due to missing <cstring>
+    + lib.optionalString ((lib.versions.major version) == "25") ''
+      sed -i '1i #include <cstring>' third_party/utf8_range/utf8_validity.cc
     '';
 
   preHook = ''