build: Correctly put boost at end of LDADD

This fixes linking issues when statically linking
(thanks @imwuzhh).

src/Makefile.am

@@ -93,8 +93,7 @@ nodist_libbitcoin_common_a_SOURCES = $(top_srcdir)/src/obj/build.h
 #
 
 # bitcoind binary #
-bitcoind_LDADD = libbitcoin_server.a libbitcoin_cli.a libbitcoin_common.a leveldb/libleveldb.a leveldb/libmemenv.a \
+bitcoind_LDADD = libbitcoin_server.a libbitcoin_cli.a libbitcoin_common.a leveldb/libleveldb.a leveldb/libmemenv.a
-  $(BOOST_LIBS)
 if ENABLE_WALLET
 bitcoind_LDADD += libbitcoin_wallet.a
 endif
@@ -106,7 +105,7 @@ bitcoind_SOURCES += bitcoind-res.rc
 endif
 
 AM_CPPFLAGS += $(BDB_CPPFLAGS)
-bitcoind_LDADD += $(BDB_LIBS)
+bitcoind_LDADD += $(BOOST_LIBS) $(BDB_LIBS)
 
 # bitcoin-cli binary #
 bitcoin_cli_LDADD = libbitcoin_cli.a libbitcoin_common.a $(BOOST_LIBS)