message: [Build] Make sure Boost headers are included for libzerocoin
  Custom boost locations not using pkg_config can result in a header
  include not being found when compiling the libzerocoin library. This
  quick fix ensures that the `BOOST_CPPFLAGS` are explicitely included.
diff: @@ -324,7 +324,7 @@ crypto_libbitcoin_crypto_a_SOURCES = \
  crypto/sph_types.h
  # libzerocoin library
  -libzerocoin_libbitcoin_zerocin_a_CPPFLAGS = $(AM_CPPFLAGS)
  +libzerocoin_libbitcoin_zerocin_a_CPPFLAGS = $(AM_CPPFLAGS) $(BOOST_CPPFLAGS)
  libzerocoin_libbitcoin_zerocin_a_CXXFLAGS = $(AM_CXXFLAGS) $(PIE_FLAGS)
  libzerocoin_libbitcoin_zerocoin_a_SOURCES = \
  libzerocoin/Accumulator.h \
  