diff --git a/CMakeLists.txt b/CMakeLists.txt
index f9e9891..06229f9 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -775,7 +775,10 @@
 # Should we cross-compile the standard library for Windows?
 is_sdk_requested(WINDOWS swift_build_windows)
 if(swift_build_windows AND NOT "${CMAKE_SYSTEM_NAME}" STREQUAL "Windows")
-  configure_sdk_windows(WINDOWS "Windows" "msvc" "aarch64;armv7;i686;x86_64")
+  if("${SWIFT_SDK_WINDOWS_ARCHITECTURES}" STREQUAL "")
+    set(SWIFT_SDK_WINDOWS_ARCHITECTURES aarch64;armv7;i686;x86_64)
+  endif()
+  configure_sdk_windows(WINDOWS "Windows" "msvc" "${SWIFT_SDK_WINDOWS_ARCHITECTURES}")
 endif()
 
 if("${SWIFT_SDKS}" STREQUAL "")