From e997d6b9686dd45aac0294b7d53a018648eda1bf Mon Sep 17 00:00:00 2001
From: Roland Conybeare <rconybeare@gmail.com>
Date: Fri, 4 Jul 2025 10:05:25 -0500
Subject: [PATCH] adjustments for darwin/clang build

---
 include/xo/unit/dimension.hpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/include/xo/unit/dimension.hpp b/include/xo/unit/dimension.hpp
index c28936e2..c926455b 100644
--- a/include/xo/unit/dimension.hpp
+++ b/include/xo/unit/dimension.hpp
@@ -2,6 +2,9 @@
 
 #pragma once
 
+#ifdef __APPL__
+# include <vector>  // for std::size_t when building with clang18
+#endif
 #include <cstdint>
 
 namespace xo {
@@ -58,7 +61,7 @@ namespace xo {
         }
 
         /** @brief number of built-in dimensions, convenient for array sizing **/
-        static constexpr std::size_t n_dim = static_cast<std::size_t>(dimension::n_dim);
+        static constexpr std::uint64_t n_dim = static_cast<std::uint64_t>(dimension::n_dim);
     } /*namespace qty*/
 } /*namespace xo*/