From bc12c7f1f42e98ae8f687c3efae86adfdf718614 Mon Sep 17 00:00:00 2001
From: Finagolfin <finagolfin@tuta.io>
Date: Mon, 11 Aug 2025 01:29:58 +0530
Subject: [PATCH] build: no longer export a VFS overlay on Windows, as it
 shouldn't be needed after swiftlang/swift#79621

---
 src/swift/CMakeLists.txt | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/src/swift/CMakeLists.txt b/src/swift/CMakeLists.txt
index a0082fb1e..2df614a9f 100644
--- a/src/swift/CMakeLists.txt
+++ b/src/swift/CMakeLists.txt
@@ -17,11 +17,20 @@ add_library(swiftDispatch
   Wrapper.swift)
 target_compile_options(swiftDispatch PRIVATE
   "SHELL:-Xcc -fblocks"
-  "SHELL:-Xcc -fmodule-map-file=${PROJECT_SOURCE_DIR}/dispatch/module.modulemap"
   "SHELL:-Xcc -I${PROJECT_SOURCE_DIR}"
   "SHELL:-Xcc -I${PROJECT_SOURCE_DIR}/src/swift/shims")
-target_compile_options(swiftDispatch PUBLIC
-  "SHELL:-vfsoverlay ${CMAKE_BINARY_DIR}/dispatch-vfs-overlay.yaml")
+if(CMAKE_SYSTEM_NAME STREQUAL "Windows")
+  if(NOT BUILT_FIRST_SDK)
+    target_compile_options(swiftDispatch PRIVATE
+      "SHELL:-Xcc -fmodule-map-file=${PROJECT_SOURCE_DIR}/dispatch/module.modulemap"
+      "SHELL:-vfsoverlay ${CMAKE_BINARY_DIR}/dispatch-vfs-overlay.yaml")
+  endif()
+else()
+  target_compile_options(swiftDispatch PRIVATE
+    "SHELL:-Xcc -fmodule-map-file=${PROJECT_SOURCE_DIR}/dispatch/module.modulemap")
+  target_compile_options(swiftDispatch PUBLIC
+    "SHELL:-vfsoverlay ${CMAKE_BINARY_DIR}/dispatch-vfs-overlay.yaml")
+endif()
 set_target_properties(swiftDispatch PROPERTIES
   Swift_MODULE_NAME Dispatch
   Swift_MODULE_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR}/swift