From 29e43c4baf9354e6b428a7927f1f04af916b412f Mon Sep 17 00:00:00 2001
From: Chris McGee <87777443+cmcgee1024@users.noreply.github.com>
Date: Wed, 16 Apr 2025 12:04:34 -0400
Subject: [PATCH] Add SDKROOT when proxying on macOS based on xcrun information
 (#316)

* Strip newlines from xcrun output
---
 Sources/SwiftlyCore/Platform.swift | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/Sources/SwiftlyCore/Platform.swift b/Sources/SwiftlyCore/Platform.swift
index 4b7291f9..0b7084e1 100644
--- a/Sources/SwiftlyCore/Platform.swift
+++ b/Sources/SwiftlyCore/Platform.swift
@@ -166,6 +166,16 @@ extension Platform {
         for (key, value) in env {
             newEnv[key] = value
         }
+
+#if os(macOS)
+        // On macOS, we try to set SDKROOT if its empty for tools like clang++ that need it to
+        // find standard libraries that aren't in the toolchain, like libc++. Here we
+        // use xcrun to tell us what the default sdk root should be.
+        if newEnv["SDKROOT"] == nil {
+            newEnv["SDKROOT"] = (try? await self.runProgramOutput("/usr/bin/xcrun", "--show-sdk-path"))?.replacingOccurrences(of: "\n", with: "")
+        }
+#endif
+
         try self.runProgram([command] + arguments, env: newEnv)
     }