Test our implementation against Cryptography module's

src/cha1block.h

@@ -43,7 +43,7 @@ static inline uint64_t _cha_block(cha_ctx* ctx, uint8_t* begin, uint8_t* end) {
             c = end;
             // Leftover bytes are stored in ctx for next call
             ctx->uncount = 64 - bytes;
-            memcpy(ctx->unconsumed, x + bytes, ctx->uncount);
+            memcpy(ctx->unconsumed, (uint8_t*)x + bytes, ctx->uncount);
             break;
         }
         memcpy(c, x, 64);