Merge pull request swiftlang#12450 from compnerd/windows-architecture

build: support cross-compiling multiple Windows SDKs

Author: compnerd

CMakeLists.txt

@@ -774,17 +774,7 @@ endif()
 # Should we cross-compile the standard library for Windows?
 is_sdk_requested(WINDOWS swift_build_windows)
 if(swift_build_windows AND NOT "${CMAKE_SYSTEM_NAME}" STREQUAL "Windows")
-  if("${SWIFT_HOST_VARIANT_ARCH}" STREQUAL "aarch64")
-    configure_sdk_windows(WINDOWS "Windows" "msvc" aarch64)
-  elseif("${SWIFT_HOST_VARIANT_ARCH}" STREQUAL "armv7")
-    configure_sdk_windows(WINDOWS "Windows" "msvc" armv7)
-  elseif("${SWIFT_HOST_VARIANT_ARCH}" STREQUAL "i686")
-    configure_sdk_windows(WINDOWS "Windows" "msvc" i686)
-  elseif("${SWIFT_HOST_VARIANT_ARCH}" STREQUAL "x86_64")
-    configure_sdk_windows(WINDOWS "Windows" "msvc" x86_64)
-  else()
-    message(FATAL_ERROR "unable to calculate triple for Windows host on ${SWIFT_HOST_VARIANT_ARCH}")
-  endif()
+  configure_sdk_windows(WINDOWS "Windows" "msvc" "aarch64;armv7;i686;x86_64")
 endif()
 
 if("${SWIFT_SDKS}" STREQUAL "")