Fix unused capture warnings and void* arithmetic (clang)

src/blockstore_write.cpp

@@ -21,7 +21,7 @@ bool blockstore_impl_t::enqueue_write(blockstore_op_t *op)
         dyn = calloc_or_die(1, dyn_size+sizeof(int));
         *((int*)dyn) = 1;
     }
-    uint8_t *dyn_ptr = (uint8_t*)(alloc_dyn_data ? dyn+sizeof(int) : &dyn);
+    uint8_t *dyn_ptr = (alloc_dyn_data ? (uint8_t*)dyn+sizeof(int) : (uint8_t*)&dyn);
     uint64_t version = 1;
     if (dirty_db.size() > 0)
     {

src/cluster_client.cpp

@@ -64,7 +64,7 @@ cluster_client_t::cluster_client_t(ring_loop_t *ringloop, timerfd_manager_t *tfd
 
 cluster_client_t::~cluster_client_t()
 {
-    msgr.repeer_pgs = [this](osd_num_t){};
+    msgr.repeer_pgs = [](osd_num_t){};
     if (ringloop)
     {
         ringloop->unregister_consumer(&consumer);
@@ -454,7 +454,7 @@ bool cluster_client_t::flush()
             wb->start_writebacks(this, 0);
             cluster_op_t *sync = new cluster_op_t;
             sync->opcode = OSD_OP_SYNC;
-            sync->callback = [this](cluster_op_t *sync)
+            sync->callback = [](cluster_op_t *sync)
             {
                 delete sync;
             };
@@ -465,7 +465,7 @@ bool cluster_client_t::flush()
     bool sync_done = false;
     cluster_op_t *sync = new cluster_op_t;
     sync->opcode = OSD_OP_SYNC;
-    sync->callback = [this, &sync_done](cluster_op_t *sync)
+    sync->callback = [&sync_done](cluster_op_t *sync)
     {
         delete sync;
         sync_done = true;

src/cluster_client_wb.cpp

@@ -263,7 +263,7 @@ void writeback_cache_t::flush_buffers(cluster_client_t *cli, dirty_buf_it_t from
     }
     assert(calc_len == op->len);
     writebacks_active++;
-    op->callback = [this, cli, flush_id](cluster_op_t* op)
+    op->callback = [this, flush_id](cluster_op_t* op)
     {
         // Buffer flushes should be always retried, regardless of the error,
         // so they should never result in an error here
@@ -383,7 +383,7 @@ static void copy_to_op(cluster_op_t *op, uint64_t offset, uint8_t *buf, uint64_t
             auto begin = (cur_offset < offset ? offset : cur_offset);
             auto end = (cur_offset+v.iov_len > offset+len ? offset+len : cur_offset+v.iov_len);
             memcpy(
-                v.iov_base + begin - cur_offset,
+                (uint8_t*)v.iov_base + begin - cur_offset,
                 buf + (cur_offset <= offset ? 0 : cur_offset-offset),
                 end - begin
             );