Merge commit 'refs/top-bases/gcc-unused' into gcc-unused

diff --cc cmd/ztest/ztest.c
Simple merge

diff --cc module/zfs/dmu.c
Simple merge

diff --cc module/zfs/dmu_objset.c
Simple merge

diff --cc module/zfs/dnode.c
Simple merge

diff --cc module/zfs/dsl_dataset.c
Simple merge

diff --cc module/zfs/dsl_dir.c
Simple merge

diff --cc module/zfs/dsl_prop.c
Simple merge

diff --cc module/zfs/spa.c
index 9b02b29e3e166d20de1fb4f7c7c53e337856c2fb,d7ed23e6fa552e1dabec40dffa3c478380ce9638..d45e070eafa4bf3291367bf08e0d08e0d7f2bbd2
--- 1/module/zfs/spa.c
--- 2/module/zfs/spa.c
+++ b/module/zfs/spa.c
@@@ -2988,10 -2998,9 +2998,9 @@@ in
  spa_vdev_attach(spa_t *spa, uint64_t guid, nvlist_t *nvroot, int replacing)
  {
        uint64_t txg, open_txg;
 -      vdev_t *rvd = spa->spa_root_vdev;
 +      ASSERTV(vdev_t *rvd = spa->spa_root_vdev;)
        vdev_t *oldvd, *newvd, *newrootvd, *pvd, *tvd;
        vdev_ops_t *pvops;
-       dmu_tx_t *tx;
        char *oldvdpath, *newvdpath;
        int newvd_isspare;
        int error;

diff --cc module/zfs/vdev.c
Simple merge

diff --cc module/zfs/zap_micro.c
Simple merge