Problem:    Wrong type for flags used in signal handlers.
Solution:   Use sig_atomic_t. (Dominique Pelle, closes #3356)

Problem:    On MS-Windows setting an environment variable with multi-byte
            strings does not work well.
Solution:   Use wputenv when possible. (Taro Muraoka, Ken Takata)

Problem:    Code for MS-Windows is complicated because of the exceptions for
            old systems.
Solution:   Drop support for MS-Windows older than Windows XP. (Ken Takata)

Problem:    Modelines in source code are inconsistant.
Solution:   Use the same line in most files.  Add 'noet'.  (Naruhiko Nishino)

Problem:    Still using HAVE_STDARG_H.
Solution:   Assume it's always defined.

Problem:    Memory use on MS-Windows is very conservative.
Solution:   Use the global memory status to estimate amount of memory.
            (Mike Williams)

Problem:    Now that the +visual feature is always enabled the #ifdefs for it
            are not useful.
Solution:   Remove the checks for FEAT_VISUAL.

Problem:    MS-Windows: MSCV10 and earlier can't handle symlinks to a
            directory properly.
Solution:   Add stat_symlink_aware() and wstat_symlink_aware(). (Ken Takata)

Problem:    When using MSVC 2012 there are various issues, including GUI size
            computations.
Solution:   Use SM_CXPADDEDBORDER. (Mike Williams)

Problem:    ACL support doesn't work when when compiled with MingW.
Solution:   Support ACL on MingW. (Ken Takata)