From 491ecfdf4673ade98e1a1370000af9b684162d39 Mon Sep 17 00:00:00 2001
From: Reno Dakota <paparodeo@proton.me>
Date: Fri, 6 Dec 2024 20:40:04 -0800
Subject: [PATCH] libpng12: fix clang-19 build

clang-19 defines TARGET_OS_MACOS which results in libpng erroneously
trying to include `fp.h` rather than `math.h`.
---
 pkgs/development/libraries/libpng/12.nix | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/pkgs/development/libraries/libpng/12.nix b/pkgs/development/libraries/libpng/12.nix
index 9792447bcc888c..46fe96aa0777a0 100644
--- a/pkgs/development/libraries/libpng/12.nix
+++ b/pkgs/development/libraries/libpng/12.nix
@@ -13,6 +13,10 @@ stdenv.mkDerivation (finalAttrs: {
     sha256 = "1izw9ybm27llk8531w6h4jp4rk2rxy2s9vil16nwik5dp0amyqxl";
   };
 
+  postPatch = lib.optionalString stdenv.hostPlatform.isDarwin ''
+    substituteInPlace pngconf.h --replace-fail '<fp.h>' '<math.h>'
+  '';
+
   outputs = [ "out" "dev" "man" ];
 
   propagatedBuildInputs = [ zlib ];