From 9b05474d797ea4600dbae36ae95d9eb042040bb2 Mon Sep 17 00:00:00 2001
From: Cody Tapscott <topolarity@tapscott.me>
Date: Fri, 10 Jun 2022 07:21:54 -0700
Subject: [PATCH] ThreadPool: Make join() a no-op in single-threaded mode

This comptime gate is needed to make sure that purely single-threaded
programs don't generate calls to the std.Thread API.

WASI targets successfully build again with this change.
---
 src/ThreadPool.zig | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/ThreadPool.zig b/src/ThreadPool.zig
index 7d1c8420af..55e40ea287 100644
--- a/src/ThreadPool.zig
+++ b/src/ThreadPool.zig
@@ -49,6 +49,10 @@ pub fn deinit(self: *ThreadPool) void {
 }
 
 fn join(self: *ThreadPool, spawned: usize) void {
+    if (builtin.single_threaded) {
+        return;
+    }
+
     {
         self.mutex.lock();
         defer self.mutex.unlock();