Merge pull request #1076 from uckelman-sf/fix_undef_stat

Windows compatibility: don't #undef stat and #define stat().

diff --cc libarchive/archive_read_disk_entry_from_file.c
Simple merge

diff --cc libarchive/archive_read_disk_posix.c
Simple merge

diff --cc libarchive/archive_write_disk_posix.c
Simple merge