Revert "Remove tagged pointer example"

This reverts commit a318362d25.

examples/Cargo.toml

@@ -5,4 +5,5 @@ members = [
   "free_by_borrow",
   "free_by_gc",
   "static_threads",
+  "tagged_pointer",
 ]

examples/tagged_pointer/Cargo.toml

@@ -0,0 +1,9 @@
+[package]
+name = "tagged_pointer"
+version = "0.1.0"
+authors = ["Yota Toyama <raviqqe@gmail.com>"]
+edition = "2021"
+publish = false
+
+[dependencies]
+bdwgc-alloc = { path = "../.." }

examples/tagged_pointer/src/main.rs

@@ -0,0 +1,21 @@
+extern crate bdwgc_alloc;
+
+use bdwgc_alloc::Allocator;
+use std::alloc::Layout;
+
+#[global_allocator]
+static GLOBAL_ALLOCATOR: Allocator = Allocator;
+
+fn main() {
+    unsafe { Allocator::initialize() }
+
+    let handle = std::thread::spawn(move || {
+        unsafe { Allocator::register_current_thread().unwrap() }
+
+        loop {
+            let _ = unsafe { std::alloc::alloc(Layout::from_size_align(2 ^ 8, 8).unwrap()) };
+        }
+    });
+
+    handle.join().unwrap();
+}