Include license and readme in build output

This is probably required for GPL compliance :-D

build.zig

@@ -7,6 +7,9 @@ const std = @import("std");
 // build runner to parallelize the build automatically (and the cache system to
 // know when a step doesn't need to be re-run).
 pub fn build(b: *std.Build) void {
+    // Ensure the license is included in the output directory
+    b.installFile("LICENSE.md", "LICENSE.md");
+    b.installFile("README.md", "README.md");
     // Standard target options allow the person running `zig build` to choose
     // what target to build for. Here we do not override the defaults, which
     // means any target is allowed, and the default is native. Other options