Add MySQL 5.6 support. https://blueprints.launchpad.net/percona-xtrabackup/+spec/build-against-mysql-56
- Add new flavor option innodb56 to utils/build.sh and test/bootstrap.sh. Add its synonym 5.6 to utils/build.sh only. Build for 5.6 using the embedded server(libmysqld) instead of cherry-picking several subdirectories.
- Add new target 5.6 to src/Makefile. Link xbstream with a C++ compiler.
- Add patches/innodb56.patch, based on innodb55.patch, developed on MySQL 5.6.10.
- src/xtrabackup.cc: account for MySQL 5.6 InnoDB internal API changes. Replace LSN64 and some of ib_uint64_t types with 5.6-introduced lsn_t. Use 5.6-introduced LSN_PF and IB_UINT64 macros for lsn_t and ib_uint64_t printf format specifiers. Rename local variables that are conflicting with libmysqld symbols. Provide implementation of open_or_create_log_file() that was removed in MySQL 5.6. Fixup format specifiers in xtrabackup_stats_level().
- Support additional mysqld flags in test/inc/common.sh at bootstrap time, set through MYSQLD_EXTRA_ARGS.
- Adjust test/t/bug1062684.sh and test/t/bug891496.sh to work with adjusted default new tablespace size in MySQL 5.6.