From d029f0426e42db95148cbc0b22a2f0b567ff83d5 Mon Sep 17 00:00:00 2001
From: Raymond Chen <oldnewthing@users.noreply.github.com>
Date: Thu, 8 Sep 2022 06:51:49 -0700
Subject: [PATCH] Don't use `__uuidof` without `GUID` (#1180)

---
 strings/base_meta.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/strings/base_meta.h b/strings/base_meta.h
index f951c4db..e80afb9b 100644
--- a/strings/base_meta.h
+++ b/strings/base_meta.h
@@ -119,12 +119,12 @@ namespace winrt::impl
 
     template <typename T>
 #if defined(__clang__)
-#if __has_declspec_attribute(uuid)
+#if __has_declspec_attribute(uuid) && defined(WINRT_IMPL_IUNKNOWN_DEFINED)
     inline const guid guid_v{ __uuidof(T) };
 #else
     inline constexpr guid guid_v{};
 #endif
-#elif defined(_MSC_VER)
+#elif defined(_MSC_VER) && defined(WINRT_IMPL_IUNKNOWN_DEFINED)
     inline constexpr guid guid_v{ __uuidof(T) };
 #else
     inline constexpr guid guid_v{};