fix src/util/hash.h to specialize GNU's hash template for <uint64_t> on platforms that need it; fixes Mac builds.

1 files changed, 4 insertions, 3 deletions

diff --git a/src/util/hash.h b/src/util/hash.h
index 5f0189d44..fdfbf4087 100644
--- a/src/util/hash.h
+++ b/src/util/hash.h
@@ -29,15 +29,16 @@ namespace __gnu_cxx {}
 
 namespace __gnu_cxx {
 
-#if __WORDSIZE == 32
-// on 32-bit, we need a specialization of hash for 64-bit values
+#ifdef CVC4_NEED_HASH_UINT64_T
+// on some versions and architectures of GNU C++, we need a
+// specialization of hash for 64-bit values
 template <>
 struct hash<uint64_t> {
   size_t operator()(uint64_t v) const {
     return v;
   }
 };/* struct hash<uint64_t> */
-#endif /* 32-bit */
+#endif /* CVC4_NEED_HASH_UINT64_T */
 
 }/* __gnu_cxx namespace */