message: Move pos.cpp into the wallet static library in order to resolve compilation problem.
diff: @@ -211,7 +211,6 @@ libbitcoin_server_a_SOURCES = \
  policy/fees.cpp \
  policy/policy.cpp \
  pow.cpp \
  - pos.cpp \
  rest.cpp \
  rpc/blockchain.cpp \
  rpc/mining.cpp \
  @@ -255,6 +254,7 @@ libbitcoin_wallet_a_SOURCES = \
  wallet/wallet.cpp \
  wallet/walletdb.cpp \
  policy/rbf.cpp \
  + pos.cpp \
  $(BITCOIN_CORE_H)
  # crypto primitives library
  