Patch #2: This patch does the following:
- Enforces Visual Studio 2013 as the minimum version of Visual Studio,
  in accordance with our supported platform list for 5.7

- Removes the unused CYBOZU and BACKUP_TEST CMake options
- Removes the following CMake checks which were always false for
  our supported platforms: HAVE_TERMBITS_H, HAVE_NDIR_H, HAVE_SELECT_H,
  HAVE_SYS_NDIR_H, HAVE_SYSENT_H, HAVE_RDTSCLL
- Removes the following CMake checks which were always true for
  our supported platforms: HAVE_SYS_TYPES_H, HAVE_FCNTL_H, HAVE_FENV_H,
  HAVE_INTTYPES_H, HAVE_STDINT_H, HAVE_SYS_STAT_H, HAVE_RINT,
  HAVE_FESETROUND
- Removes the following CMake checks where the results are not needed:
  HAVE_SYS_DIR_H, HAVE_DLERROR, HAVE_ASM_MSR_H, HAVE_DECL_MADVISE

- Moves the defintion of NOGDI from my_global.h to the Windows CMake
  file so its defintion no longer depends on including my_global.h
- Moves the defintion of __EXTENSIONS, _POSIX_THREAD_SEMANTICS and
  _REENTRANT from my_global.h to the Solaris CMake file so their
  defintion no longer depends on including my_global.h
- Moves the HAVE_SOLARIS_STYLE_GETHOST CMake check to the Solaris
  CMake file so that it is not run on all platforms

- Removes use of #_lint
- Removes use of TARGET_OS_LINUX, use __linux__ instead
- Removes use of HAVE_LONG_LONG, always true
- Removes various __GNUC__ version checks which are no longer relevant
- Changes remaining use of DBUG_ON to !DBUG_OFF

- Removes setting of _GNU_SOURCE from my_global.h, already set by CMake
- Removes setting of _THREAD_SAFE from my_global.h, not needed
- Removes declaration of madvise from my_global.h, not used
- Removes duplicate declaration of closesocket from my_global.h
- Removes STACK_DIRECTION check from my_global.h, already done by CMake
- Removes various defintions from my_global, use limits.h instead

- Removes many unused declarations from my_sys.h and my_static.h
- Removes various definitions of __attribute__, use my_compiler.h instead

- Removes the following files with only dead code: include/t_ctype.h,
  mysys/my_getncpus.c
- Removes dead code from mysys/my_getsystime.c
- Removes mysys/mf_sort.c and moves used code to bounded_queue unit test

- Removes st_my_thread_var::cmp_length, not used
- Removes st_my_thread_var::pthread_self, use pthread_self() instead