Merge #7349: Build against system UniValue when available
42407ed build-unix: Update UniValue build conditions (Luke Dashjr)
cdcad9f LDADD dependency order shuffling (Luke Dashjr)
62f7f2e Bugfix: Always include univalue in DIST_SUBDIRS (Luke Dashjr)
2356515 Change default configure option --with-system-univalue to "no" (Luke Dashjr)
5d3b29b doc: Add UniValue to build instructions (Luke Dashjr)
ab22705 Build against system UniValue when available (Luke Dashjr)
2adf7e2 Bugfix: The var is LIBUNIVALUE,not LIBBITCOIN_UNIVALUE (Luke Dashjr)