From bdf60d39d5e0802ad69929f5a099bdc394608f7f Mon Sep 17 00:00:00 2001
From: Peter Dimov <pdimov@gmail.com>
Date: Sat, 6 Jan 2024 17:05:58 +0200
Subject: [PATCH] Avoid -Wundef warning

---
 include/boost/exception/exception.hpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/boost/exception/exception.hpp b/include/boost/exception/exception.hpp
index ca8d833..4ec18d7 100644
--- a/include/boost/exception/exception.hpp
+++ b/include/boost/exception/exception.hpp
@@ -19,7 +19,7 @@ namespace boost { namespace exception_detail { using boost::shared_ptr; } }
 #endif
 
 #if !defined(BOOST_EXCEPTION_ENABLE_WARNINGS)
-#if __GNUC__*100+__GNUC_MINOR__>301
+#if defined(__GNUC__) && __GNUC__*100+__GNUC_MINOR__>301
 #pragma GCC system_header
 #endif
 #ifdef __clang__