Fix:

/opt/local/include/google/protobuf/arena_impl.h:62:34: error: unknown type name 'max_align_t'; did you mean 'std::max_align_t'?
--- src/google/protobuf/arena_impl.h.orig	2022-12-14 08:20:05.000000000 -0600
+++ src/google/protobuf/arena_impl.h	2026-04-24 01:36:05.000000000 -0500
@@ -34,6 +34,7 @@
 #define GOOGLE_PROTOBUF_ARENA_IMPL_H__
 
 #include <atomic>
+#include <cstddef>
 #include <limits>
 #include <typeinfo>
 
@@ -59,7 +60,7 @@
 #ifdef __cpp_aligned_new
 enum { kCacheAlignment = 64 };
 #else
-enum { kCacheAlignment = alignof(max_align_t) };  // do the best we can
+enum { kCacheAlignment = alignof(std::max_align_t) };  // do the best we can
 #endif
 
 inline constexpr size_t AlignUpTo8(size_t n) {
