From 4d048053ff68278e13d60d60de88c1d70a999d7a Mon Sep 17 00:00:00 2001
From: Ross Goldberg <484615+rgoldberg@users.noreply.github.com>
Date: Wed, 12 Feb 2025 02:40:01 -0500
Subject: [PATCH] Prevent implementation-only import build warnings on older
 Swift.

Resolve #719

Signed-off-by: Ross Goldberg <484615+rgoldberg@users.noreply.github.com>
---
 Sources/ArgumentParser/Utilities/Mutex.swift | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Sources/ArgumentParser/Utilities/Mutex.swift b/Sources/ArgumentParser/Utilities/Mutex.swift
index 306734712..314bd60b3 100644
--- a/Sources/ArgumentParser/Utilities/Mutex.swift
+++ b/Sources/ArgumentParser/Utilities/Mutex.swift
@@ -9,7 +9,13 @@
 //
 //===----------------------------------------------------------------------===//
 
+#if swift(>=5.11)
+internal import Foundation
+#elseif swift(>=5.10)
 import Foundation
+#else
+@_implementationOnly import Foundation
+#endif
 
 /// A synchronization primitive that protects shared mutable state via mutual
 /// exclusion.