message: Add -v to CXXFLAGS temporarily
diff: DIST_SUBDIRS = secp256k1 univalue
  AM_LDFLAGS = $(PTHREAD_CFLAGS) $(LIBTOOL_LDFLAGS) $(HARDENED_LDFLAGS)
  -AM_CXXFLAGS = $(HARDENED_CXXFLAGS) $(ERROR_CXXFLAGS) -DETH_FATDB=1
  +AM_CXXFLAGS = $(HARDENED_CXXFLAGS) $(ERROR_CXXFLAGS) -DETH_FATDB=1 -v
  AM_CPPFLAGS = $(HARDENED_CPPFLAGS)
  EXTRA_LIBRARIES =
  