Prevent building example when use as module

build.zig

@@ -29,6 +29,7 @@ pub fn build(b: *std.Build) !void {
         mod.linkSystemLibrary("gcc_s", .{});
     }
 
+    if (b.pkg_hash.len == 0) {
         var threaded: std.Io.Threaded = .init_single_threaded;
         const io = threaded.io();
 
@@ -57,3 +58,4 @@ pub fn build(b: *std.Build) !void {
             run_step.dependOn(&run_cmd.step);
         }
     }
+}