No, xbstream is not related to innodb51 and should stay. It is built regardless of arguments to build.sh, but resulting binaries are the same functionality-wise. So it doesn't matter which build configuration is used to produce xbstream for packaging.
No, xbstream is not related to innodb51 and should stay. It is built regardless of arguments to build.sh, but resulting binaries are the same functionality-wise. So it doesn't matter which build configuration is used to produce xbstream for packaging.