add nix to runtime with build options instead of a wrapper

build.zig

@@ -3,12 +3,18 @@ const std = @import("std");
 pub fn build(b: *std.Build) void {
     const target = b.standardTargetOptions(.{});
     const optimize = b.standardOptimizeOption(.{});
+    const nix = b.option([]const u8, "nix", "Path to the Nix executable") orelse "nix";
+
+    const options = b.addOptions();
+    options.addOption([]const u8, "nix", nix);
+
     const exe = b.addExecutable(.{
         .name = "zon2nix",
         .root_source_file = .{ .path = "src/main.zig" },
         .target = target,
         .optimize = optimize,
     });
+    exe.addOptions("options", options);
     exe.linkLibC();
     b.installArtifact(exe);
 
@@ -25,6 +31,7 @@ pub fn build(b: *std.Build) void {
         .target = target,
         .optimize = optimize,
     });
+    unit_tests.addOptions("options", options);
     unit_tests.linkLibC();
     const run_unit_tests = b.addRunArtifact(unit_tests);
     const test_step = b.step("test", "Run unit tests");

flake.nix

@@ -19,10 +19,9 @@
       perSystem = { lib, pkgs, ... }:
         let
           inherit (lib)
-            makeBinPath
+            getExe
             ;
           inherit (pkgs)
-            makeBinaryWrapper
             nix
             stdenv
             zigHook
@@ -37,16 +36,18 @@
             src = ./.;
 
             nativeBuildInputs = [
-              makeBinaryWrapper
               (zigHook.override {
                 zig = zig_0_11;
               })
             ];
 
-            postInstall = ''
-              wrapProgram $out/bin/zon2nix \
-                --prefix PATH : ${makeBinPath [ nix ]}
-            '';
+            zigBuildFlags = [
+              "-Dnix=${getExe nix}"
+            ];
+
+            zigCheckFlags = [
+              "-Dnix=${getExe nix}"
+            ];
           };
         };
     };

src/fetch.zig

@@ -8,6 +8,8 @@ const fs = std.fs;
 const json = std.json;
 const log = std.log;
 
+const nix = @import("options").nix;
+
 const Dependency = @import("Dependency.zig");
 const parse = @import("parse.zig").parse;
 
@@ -34,7 +36,7 @@ pub fn fetch(alloc: Allocator, deps: *StringHashMap(Dependency)) !void {
 
             var child = try alloc.create(ChildProcess);
             const ref = try fmt.allocPrint(alloc, "tarball+{s}", .{dep.url});
-            const argv = &[_][]const u8{ "nix", "flake", "prefetch", "--json", "--extra-experimental-features", "flakes nix-command", ref };
+            const argv = &[_][]const u8{ nix, "flake", "prefetch", "--json", "--extra-experimental-features", "flakes nix-command", ref };
             child.* = ChildProcess.init(argv, alloc);
             child.stdin_behavior = .Ignore;
             child.stdout_behavior = .Pipe;