* PHP-7.3:
  Fix #79566: Private SHM is not private on Windows

We map the POSIX semantics of `IPC_PRIVATE` by creating unnamed file
mapping objects on Windows.  While that is not particularly useful for
ext/shmop, which is the only bundled extension which uses `shmget()`,
it may be useful for external extensions.

* PHP-7.3:
  Fix #78538: shmop memory leak

If the descriptor's refcount drops to zero, we have to unmap the
respective file view, to avoid leaking memory.

* PHP-7.2:
  Fix #78282: atime and mtime mismatch

The fix for bug #78241 assumed that `time_t` would always be 64bit, but
actually is 32bit for x86.  We therefore enforce 64bit arithmetic to
avoid wrapping.

(cherry picked from commit bf242d58e77d50d4d8fdaaaca7ede686ec4467c0)

The fix for bug #78241 assumed that `time_t` would always be 64bit, but
actually is 32bit for x86.  We therefore enforce 64bit arithmetic to
avoid wrapping.

- Checks and defines are not relevant for files that include it anymore
- Some code is not used anymore
- Defines are a bit duplicated in zend_portability.h and TSRM.h file
- MAXPATHLEN defs moved to zend_virtual_cwd.h

There is also a php_strtok_r() function, which is actually used,
but nothing uses the tsrm_strtok_r() variant...

The tsrm_config.w32.h file is a simple wrapper for already defined
symbols and includes elsewhere.

Closes GH-4383