singular, gfan: fix the same clang-19 error (#370174)

pkgs/by-name/gf/gfan/package.nix

@@ -19,6 +19,14 @@ stdenv.mkDerivation rec {
   patches =
     [
       ./gfan-0.6.2-cddlib-prefix.patch
+      (fetchpatch {
+        # removes dead code with invalid member reference in gfanlib
+        name = "clang-19.patch";
+        url = "https://github.com/Singular/Singular/commit/d3f73432d73ac0dd041af83cb35301498e9b57d9.patch";
+        stripLen = 2;
+        extraPrefix = "src/";
+        hash = "sha256-jPGMYx/GOFV7Tk3CqaRWeX/UHkzjeL57eZj4r40s8/g=";
+      })
     ]
     ++ lib.optionals (stdenv.cc.isClang) [
       (fetchpatch {

pkgs/by-name/si/singular/package.nix

@@ -1,6 +1,7 @@
 {
   stdenv,
   fetchFromGitHub,
+  fetchpatch,
   gmp,
   bison,
   perl,
@@ -48,6 +49,15 @@ stdenv.mkDerivation rec {
     forceFetchGit = true;
   };
 
+  patches = [
+    (fetchpatch {
+      # removes dead code with invalid member reference in gfanlib
+      name = "clang-19.patch";
+      url = "https://github.com/Singular/Singular/commit/d3f73432d73ac0dd041af83cb35301498e9b57d9.patch";
+      hash = "sha256-1KOk+yrTvHWY4aSK9QcByHIwKwe71QIYTMx8zo7XNos=";
+    })
+  ];
+
   configureFlags =
     [
       "--enable-gfanlib"
@@ -173,6 +183,7 @@ stdenv.mkDerivation rec {
   '';
 
   enableParallelBuilding = true;
+  __darwinAllowLocalNetworking = true;
 
   meta = with lib; {
     description = "CAS for polynomial computations";