restore: add snapmk snapshot repacker

Adds a utility that compresses a snapshot.tar into a backwards-
compatible snapshot.tar.zst that can be trivially streaming
decompressed in parallel (requires no seek ability).

Beats zstdmt version 1.5.5 by about 50-100% in parallel mode.

Author: riptl

src/discof/restore/Local.mk

@@ -43,3 +43,9 @@ endif
 $(call add-objs,utils/fd_ssarchive,fd_discof)
 $(call add-objs,utils/fd_sspeer_selector,fd_discof)
 $(call add-objs,utils/fd_vinyl_io_wd,fd_discof)
+
+ifdef FD_HAS_HOSTED
+ifdef FD_HAS_ZSTD
+$(call make-bin,fd_snapmk_para,fd_snapmk_para,fd_discof fd_flamenco fd_ballet fd_tango fd_util)
+endif
+endif