FITS: generating send-streams in portable format
This commit adds the command 'zfs fits-send', analogous to zfs send. The
generated send stream is compatible with the stream generated with that
from 'btrfs send' and can in principle easily be received to any filesystem.

@@ -1338,10 +1338,16 @@
         dmu_send.o              \
         dmu_object.o            \
         dmu_objset.o            \
         dmu_traverse.o          \
         dmu_tx.o                \
+        fits.o                  \
+        fits_pass1.o            \
+        fits_pass2.o            \
+        fits_send.o             \
+        fits_crc32c.o           \
+        fits_count.o            \
         dnode.o                 \
         dnode_sync.o            \
         dsl_dir.o               \
         dsl_dataset.o           \
         dsl_deadlist.o          \