message: fix makefile to properly compile xversionkeys.h on windows
diff: @@ -223,6 +223,9 @@ obj/build.h: FORCE
  $(abs_top_srcdir)
  libbitcoin_util_a-clientversion.$(OBJEXT): obj/build.h
  +xversionkeys.h:
  + $(PYTHON) $(top_srcdir)/contrib/devtools/xversionkeys.py > $(abs_top_builddir)/src/xversionkeys.h < $(srcdir)/xversionkeys.dat
  +
  BUILT_SOURCES= xversionkeys.h
  # server: shared between bitcoind and bitcoin-qt
  @@ -474,10 +477,6 @@ libbitcoin_cli_a_SOURCES = \
  nodist_libbitcoin_util_a_SOURCES = $(srcdir)/obj/build.h
  #
  -# xversionkeys.h rule
  -xversionkeys.h: $(srcdir)/xversionkeys.dat $(top_srcdir)/contrib/devtools/xversionkeys.py
  - python3 $(top_srcdir)/contrib/devtools/xversionkeys.py > $(abs_top_builddir)/src/xversionkeys.h < $<
  -
  # bitcoind binary #
  bitcoind_SOURCES = bitcoind.cpp
  bitcoind_CPPFLAGS = $(AM_CPPFLAGS) $(BITCOIN_INCLUDES)
  