#417 WIN32: MSVC: add POSIX stat macro for Windows Kits.

[Carlo Bramini]

MSVC cannot build source code using macros like S_ISREG(), etc, because they are not supported by system includes. I added them into src/arch/shared/archdep_stat.h (it seems to me that it was the right place) with a special test on MSVC and src/arch/shared/archdep_default_logger.c includes archdep.h instead of archdep_defs.h for having this change available into the affected source file.

[gpz]

slightly massaged patch applied in r45874, thanks!