pe-parse: drop `no-sign-conversion` compile flag

Upstream has merged a patch to fix the issue so we can use that instead
of being lax when compiling.

pkgs/development/libraries/pe-parse/default.nix

···
-{ stdenv, lib, fetchFromGitHub, cmake }:
+{ stdenv, lib, fetchFromGitHub, cmake, fetchpatch }:
 
 stdenv.mkDerivation rec {
   pname = "pe-parse";
···
     hash = "sha256-HwWlMRhpB/sa/JRyAZF7LZzkXCCyuxB+gtDAfHt7e6k=";
   };
 
-  nativeBuildInputs = [ cmake ];
+  patches = [
+    (fetchpatch {
+      url = "https://github.com/trailofbits/pe-parse/commit/eecdb3d36eb44e306398a2e66e85490f9bdcc74c.patch";
+      hash = "sha256-pd6D/JMctiQqJxnJU9Nm/GDVf4/CaIGeXx1UfdcCupo=";
+    })
+  ];
 
-  # See https://github.com/trailofbits/pe-parse/issues/169
-  NIX_CFLAGS_COMPILE = "-Wno-sign-conversion";
+  nativeBuildInputs = [ cmake ];
 
   doInstallCheck = true;
   installCheckPhase = ''