convertlit: fix build with GCC 14

pkgs/by-name/co/convertlit/package.nix

···
   libtommath,
 }:
 
-stdenv.mkDerivation rec {
+stdenv.mkDerivation (finalAttrs: {
   pname = "convertlit";
   version = "1.8";
 
   src = fetchzip {
-    url = "http://www.convertlit.com/convertlit${lib.replaceStrings [ "." ] [ "" ] version}src.zip";
+    url = "http://www.convertlit.com/convertlit${
+      lib.replaceStrings [ "." ] [ "" ] finalAttrs.version
+    }src.zip";
     sha256 = "182nsin7qscgbw2h92m0zadh3h8q410h5cza6v486yjfvla3dxjx";
     stripRoot = false;
   };
···
 
   hardeningDisable = [ "format" ];
 
+  env.NIX_CFLAGS_COMPILE = "-Wno-error=implicit-function-declaration";
+
+  postPatch = ''
+    substituteInPlace clit18/Makefile --replace gcc \$\(CC\)
+    substituteInPlace clit18/Makefile --replace ../libtommath-0.30/libtommath.a -ltommath
+  '';
+
   buildPhase = ''
     cd lib
     make
     cd ../clit18
-    substituteInPlace Makefile \
-      --replace ../libtommath-0.30/libtommath.a -ltommath
     make
   '';
 
   installPhase = ''
-    mkdir -p $out/bin
-    cp clit $out/bin
+    install -Dm755 clit $out/bin/clit
   '';
 
   meta = {
···
     license = lib.licenses.gpl2Plus;
     platforms = lib.platforms.linux;
   };
-}
+})