Style, remove dead code.

Author: evoskuil

include/bitcoin/system/hash/pbkd.hpp

@@ -56,7 +56,7 @@ struct pbkd
 
 protected:
     template <size_t Length>
-    static constexpr auto xor_n(data_array<Length>& to,
+    static constexpr void xor_n(data_array<Length>& to,
         const data_array<Length>& from) NOEXCEPT;
 };
 

include/bitcoin/system/impl/hash/hmac.ipp

@@ -90,7 +90,7 @@ xor_n(block_t& pad, const byte_t* key, size_t size) NOEXCEPT
     // append zeros to the end of K to create a B byte string [skip].
     // XOR (bitwise exclusive-OR) the B byte string ... with [ipad/opad].
     // [not xoring beyond K length is the same as xoring that with zero].
-    for (size_t i = 0; i < size; ++i)
+    for (size_t i{}; i < size; ++i)
         pad[i] ^= key[i];
 
     return pad;

include/bitcoin/system/impl/hash/pbkd.ipp

@@ -36,12 +36,12 @@ BC_PUSH_WARNING(NO_ARRAY_INDEXING)
 // static/protected
 TEMPLATE
 template <size_t Length>
-constexpr auto CLASS::
+constexpr void CLASS::
 xor_n(data_array<Length>& to, const data_array<Length>& from) NOEXCEPT
 {
     // rfc8018
     // F (P, S, c, i) = U_1 \xor U_2 \xor ... \xor U_c
-    for (size_t i = 0; i < Length; ++i)
+    for (size_t i{}; i < Length; ++i)
         to[i] ^= from[i];
 };