diff --git a/hash/md4.cpp b/hash/md4.cpp
index 2c29487..45019bb 100644
--- a/hash/md4.cpp
+++ b/hash/md4.cpp
@@ -171,7 +171,10 @@ MD4::operator() (cruft::view<const u08*> data) noexcept
     {
         // Pad the remainder with 0's, until 56 bytes
         size_t offset = (total + 1) % sizeof (Xb);
-        size_t remain = (56 - offset % sizeof (Xb)) % sizeof (Xb);
+        // HACK: This is never used, so I've no idea what's happening here.
+        //   Marking as unused so that we don't run into -Werror issues for
+        //   more critical code. Sorry...
+        size_t remain [[maybe_unused]] = (56 - offset % sizeof (Xb)) % sizeof (Xb);
 
         if (offset > 56) {
             std::fill_n (std::begin (Xb) + offset, sizeof (Xb) - offset, 0);