build: support SWIFT_MODULE_DEPENDS_WINDOWS

Add support for depending on swift modules for the windows target.  This
is needed as the private swift modules start to build on Windows.

Author: compnerd

cmake/modules/AddSwift.cmake

@@ -1619,6 +1619,7 @@ function(add_swift_target_library name)
         SWIFT_MODULE_DEPENDS_OSX
         SWIFT_MODULE_DEPENDS_TVOS
         SWIFT_MODULE_DEPENDS_WATCHOS
+        SWIFT_MODULE_DEPENDS_WINDOWS
         TARGET_SDKS)
 
   cmake_parse_arguments(SWIFTLIB
@@ -1742,6 +1743,9 @@ function(add_swift_target_library name)
     elseif(${sdk} STREQUAL HAIKU)
       list(APPEND swiftlib_module_depends_flattened
            ${SWIFTLIB_SWIFT_MODULE_DEPENDS_HAIKU})
+    elseif(${sdk} STREQUAL WINDOWS)
+      list(APPEND swiftlib_module_depends_flattened
+           ${SWIFTLIB_SWIFT_MODULE_DEPENDS_WINDOWS})
     endif()
 
     # Collect architecture agnostic SDK framework dependencies