From e002920d8c9875f21e69e97960f897ac00fdf318 Mon Sep 17 00:00:00 2001
From: Daiderd Jordan <daiderd@gmail.com>
Date: Wed, 1 Jul 2020 20:58:30 +0200
Subject: [PATCH] libwebsockets: fix clang build

---
 pkgs/development/libraries/libwebsockets/default.nix | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pkgs/development/libraries/libwebsockets/default.nix b/pkgs/development/libraries/libwebsockets/default.nix
index ddafc9bc659..ff6fdeb5383 100644
--- a/pkgs/development/libraries/libwebsockets/default.nix
+++ b/pkgs/development/libraries/libwebsockets/default.nix
@@ -17,7 +17,7 @@ let
     nativeBuildInputs = [ cmake ];
 
     cmakeFlags = [ "-DLWS_WITH_PLUGINS=ON" ];
-    NIX_CFLAGS_COMPILE = "-Wno-error=unused-but-set-variable";
+    NIX_CFLAGS_COMPILE = stdenv.lib.optionalString stdenv.cc.isGNU "-Wno-error=unused-but-set-variable";
 
     meta = with stdenv.lib; {
       description = "Light, portable C library for websockets";