From 36d3eb27cf54bb1dedc794a8bacd455067158360 Mon Sep 17 00:00:00 2001
From: Robert Scott <code@humanleg.org.uk>
Date: Tue, 29 Aug 2023 21:50:40 +0100
Subject: [PATCH] fortify-headers: patch wchar.h's include behaviour

---
 .../libraries/fortify-headers/default.nix     |  4 ++
 .../fortify-headers/wchar-imports-skip.patch  | 41 +++++++++++++++++++
 2 files changed, 45 insertions(+)
 create mode 100644 pkgs/development/libraries/fortify-headers/wchar-imports-skip.patch

diff --git a/pkgs/development/libraries/fortify-headers/default.nix b/pkgs/development/libraries/fortify-headers/default.nix
index 2c24665456b7..9a728619266f 100644
--- a/pkgs/development/libraries/fortify-headers/default.nix
+++ b/pkgs/development/libraries/fortify-headers/default.nix
@@ -15,6 +15,10 @@ stdenv.mkDerivation {
     hash = "sha256-8A8JcKHIBgXpUuIP4zs3Q1yBs5jCGd5F3H2E8UN/S2g=";
   };
 
+  patches = [
+    ./wchar-imports-skip.patch
+  ];
+
   installPhase = ''
     runHook preInstall
 
diff --git a/pkgs/development/libraries/fortify-headers/wchar-imports-skip.patch b/pkgs/development/libraries/fortify-headers/wchar-imports-skip.patch
new file mode 100644
index 000000000000..255ceba9f099
--- /dev/null
+++ b/pkgs/development/libraries/fortify-headers/wchar-imports-skip.patch
@@ -0,0 +1,41 @@
+wchar.h: only include other headers if _FORTIFY_SOURCE is enabled
+
+unexpectedly including other headers can cause problems with
+sensitive/brittle code, particularly with alternative compilers
+(clang) which are already operating on the margins of what's
+supported/expected by some projects.
+
+having a way to almost entirely short-circuit these headers (by
+disabling _FORTIFY_SOURCE) is therefore important.
+
+--- a/include/fortify/wchar.h
++++ b/include/fortify/wchar.h
+@@ -20,21 +20,23 @@
+ #if !defined(__cplusplus) && !defined(__clang__)
+ __extension__
+ #endif
+-#include_next <limits.h>
++#include_next <wchar.h>
++
++#if defined(_FORTIFY_SOURCE) && _FORTIFY_SOURCE > 0 && defined(__OPTIMIZE__) && __OPTIMIZE__ > 0
++
+ #if !defined(__cplusplus) && !defined(__clang__)
+ __extension__
+ #endif
+-#include_next <stdlib.h>
++#include_next <limits.h>
+ #if !defined(__cplusplus) && !defined(__clang__)
+ __extension__
+ #endif
+-#include_next <string.h>
++#include_next <stdlib.h>
+ #if !defined(__cplusplus) && !defined(__clang__)
+ __extension__
+ #endif
+-#include_next <wchar.h>
++#include_next <string.h>
+ 
+-#if defined(_FORTIFY_SOURCE) && _FORTIFY_SOURCE > 0 && defined(__OPTIMIZE__) && __OPTIMIZE__ > 0
+ #include "fortify-headers.h"
+ 
+ #ifdef __cplusplus