message: build: if VERSION_BUILD is non-zero, include it in the package version
  When the build number (CLIENT_VERSION_BUILD) is non-zero, we want
  to include that in the package version number so the resulting binaries
  are named with the correct version.
diff: @@ -8,7 +8,7 @@ define(_CLIENT_VERSION_IS_RELEASE, false)
  define(_COPYRIGHT_YEAR, 2018)
  define(_COPYRIGHT_HOLDERS,[The %s developers])
  define(_COPYRIGHT_HOLDERS_SUBSTITUTION,[[Bitcoin Core]])
  -AC_INIT([Bitcoin Core],[_CLIENT_VERSION_MAJOR._CLIENT_VERSION_MINOR._CLIENT_VERSION_REVISION],[https://github.com/bitcoin/bitcoin/issues],[bitcoin],[https://bitcoincore.org/])
  +AC_INIT([Bitcoin Core],m4_join([.], _CLIENT_VERSION_MAJOR, _CLIENT_VERSION_MINOR, _CLIENT_VERSION_REVISION, m4_if(_CLIENT_VERSION_BUILD, [0], [], _CLIENT_VERSION_BUILD)),[https://github.com/bitcoin/bitcoin/issues],[bitcoin],[https://bitcoincore.org/])
  AC_CONFIG_SRCDIR([src/validation.cpp])
  AC_CONFIG_HEADERS([src/config/bitcoin-config.h])
  AC_CONFIG_AUX_DIR([build-aux])
  