From 61443e9d9060c01a80797ebf539dd1c59008192b Mon Sep 17 00:00:00 2001
From: Alexis Hildebrandt <afh@surryhill.net>
Date: Fri, 26 Jul 2024 16:05:53 +0200
Subject: [PATCH] faiss: fix build with swig 4.2

---
 .../development/libraries/science/math/faiss/default.nix | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/pkgs/development/libraries/science/math/faiss/default.nix b/pkgs/development/libraries/science/math/faiss/default.nix
index 9b7b4d268197..ac19356d1a73 100644
--- a/pkgs/development/libraries/science/math/faiss/default.nix
+++ b/pkgs/development/libraries/science/math/faiss/default.nix
@@ -63,6 +63,15 @@ stdenv.mkDerivation {
     })
   ];
 
+  postPatch = ''
+    # Remove the following substituteInPlace when updating
+    # to a release that contains change from PR
+    # https://github.com/facebookresearch/faiss/issues/3239
+    # that fixes building faiss with swig 4.2.x
+    substituteInPlace faiss/python/swigfaiss.swig \
+      --replace-fail '#ifdef SWIGWORDSIZE64' '#if (__SIZEOF_LONG__ == 8)'
+  '';
+
   buildInputs = [
     blas
     swig