From db02f97850f6676b1f879e40eeb0c04e08c4fcbd Mon Sep 17 00:00:00 2001
From: Saran Tunyasuvunakool <stunya@google.com>
Date: Wed, 15 Oct 2025 15:10:30 +0000
Subject: [PATCH] Add a missing `#include <version>` to Core.

---
 Eigen/Core | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/Eigen/Core b/Eigen/Core
index 4ce2ed972..34838f5d7 100644
--- a/Eigen/Core
+++ b/Eigen/Core
@@ -106,6 +106,11 @@
 #include <thread>
 #endif
 
+// for __cpp_lib feature test macros
+#if defined(__has_include) && __has_include(<version>)
+#include <version>
+#endif
+
 // for std::bit_cast()
 #if defined(__cpp_lib_bit_cast) && __cpp_lib_bit_cast >= 201806L
 #include <bit>