Mark functions as static

Mark functions used only in the same translation unit as static. This
only includes functions that do not have a prototype in a header file
either.

Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Closes #10470

lib/libzfs/libzfs_dataset.c

@@ -806,7 +806,7 @@ libzfs_mnttab_init(libzfs_handle_t *hdl)
 	    sizeof (mnttab_node_t), offsetof(mnttab_node_t, mtn_node));
 }
 
-int
+static int
 libzfs_mnttab_update(libzfs_handle_t *hdl)
 {
 	struct mnttab entry;
@@ -1620,7 +1620,7 @@ error:
 	return (NULL);
 }
 
-int
+static int
 zfs_add_synthetic_resv(zfs_handle_t *zhp, nvlist_t *nvl)
 {
 	uint64_t old_volsize;
@@ -2551,7 +2551,7 @@ struct get_clones_arg {
 	char buf[ZFS_MAX_DATASET_NAME_LEN];
 };
 
-int
+static int
 get_clones_cb(zfs_handle_t *zhp, void *arg)
 {
 	struct get_clones_arg *gca = arg;
@@ -3129,7 +3129,7 @@ zfs_prop_get_int(zfs_handle_t *zhp, zfs_prop_t prop)
 	return (val);
 }
 
-int
+static int
 zfs_prop_set_int(zfs_handle_t *zhp, zfs_prop_t prop, uint64_t val)
 {
 	char buf[64];