(trunk, libt) #4160 - the slow slog to catch trunk up to mike.dld's 4160 diff continues. This step applies 4160-03b-file.patch, which replaces native file operations with the tr_sys_file_*() portability wrappers added in r14321.

git-svn-id: file:///data/workdir/Transmission-svn//trunk@14327 1bcf1a7e-6170-4b50-b784-84ec52b2dec6