Fix HasVersion.

1 files changed, 2 insertions, 2 deletions

diff --git a/c/data.h b/c/data.h
index 51132f6..7e86955 100644
--- a/c/data.h
+++ b/c/data.h
@@ -58,11 +58,11 @@ struct CfgA
 template <typename T>
 constexpr inline unsigned char Version = T{}.version;
 
-template <typename T, typename = void>
+template <typename T, typename = int>
 constexpr inline bool HasVersion = false;
 
 template <typename T>
-constexpr inline bool HasVersion<T, std::void_t<typename T::version>> = true;
+constexpr inline bool HasVersion<T, decltype((void) T::version, 0)> = true;
 
 /* FileView objects manage a memory-mapped file. The view buffer may
  * be treated as an array of a given type T. Note that reading and