Revert "Use `sync.Mutex` rather than a spin lock for the threading example"

This reverts commit 8d1f46d837efdcebaf2e3660942a93337a230329.

examples/demo/demo.odin

@@ -1,15 +1,14 @@
 package main
 
 import "core:fmt"
-import "core:intrinsics"
-import "core:math/big"
 import "core:mem"
 import "core:os"
-import "core:reflect"
-import "core:runtime"
-import "core:sync"
 import "core:thread"
 import "core:time"
+import "core:reflect"
+import "core:runtime"
+import "core:intrinsics"
+import "core:math/big"
 
 /*
 	Odin is a general-purpose programming language with distinct typing built
@@ -1101,18 +1100,19 @@ parametric_polymorphism :: proc() {
 	}
 }
 
-threading_example :: proc() {
-	@static prefix_table := [?]string{
-		"White",
-		"Red",
-		"Green",
-		"Blue",
-		"Octarine",
-		"Black",
-	}
 
-	@static print_mutex: sync.Mutex
+prefix_table := [?]string{
+	"White",
+	"Red",
+	"Green",
+	"Blue",
+	"Octarine",
+	"Black",
+}
+
+print_mutex := b64(false)
 
+threading_example :: proc() {
 	fmt.println("\n# threading_example")
 
 	did_acquire :: proc(m: ^b64) -> (acquired: bool) {
@@ -1161,10 +1161,12 @@ threading_example :: proc() {
 		task_proc :: proc(t: thread.Task) {
 			index := t.user_index % len(prefix_table)
 			for iteration in 1..=5 {
-				if sync.guard(&print_mutex) {
-					fmt.printf("Worker Task %d is on iteration %d\n", t.user_index, iteration)
-					fmt.printf("`%s`: iteration %d\n", prefix_table[index], iteration)
-				}
+				for !did_acquire(&print_mutex) { thread.yield() } // Allow one thread to print at a time.
+
+				fmt.printf("Worker Task %d is on iteration %d\n", t.user_index, iteration)
+				fmt.printf("`%s`: iteration %d\n", prefix_table[index], iteration)
+
+				print_mutex = false
 
 				time.sleep(1 * time.Millisecond)
 			}
@@ -1189,10 +1191,11 @@ threading_example :: proc() {
 			time.sleep(5 * time.Millisecond)
 
 			// Allow one thread to print at a time.
-			sync.guard(&print_mutex)
+			for !did_acquire(&print_mutex) { thread.yield() }
 
 			thread.terminate(pool.threads[N - 1], 0)
 			fmt.println("Canceled last thread")
+			print_mutex = false
 		}
 
 		thread.pool_finish(&pool)