#9 Fix "no member named 'st_atim' in 'struct stat'" on macOS

[Zhiming Wang]

On macOS (10.12.5), compiling the default branch (19:a9d8ace0ee2f) results in:

src/optk/io.c:768:25: error: no member named 'st_atim' in 'struct stat'
        times[0] = sbuf.st_atim;
                   ~~~~ ^
src/optk/io.c:769:25: error: no member named 'st_mtim' in 'struct stat'
        times[1] = sbuf.st_mtim;
                   ~~~~ ^
2 errors generated.

This is because AT_FDCWD is defined on macOS, but there are no st_atim and st_mtim in struct stat, only st_atime, st_mtime, st_atimespec, and st_mtimespec. (I'm attaching the stat.2 man page).

The attached patch simply tests APPLE before using st_atim and st_mtim.

[Yuen Ho Wong]

I think a better fix is to do something like this:

#if defined AT_FDCWD && defined UTIME_NOW && defined UTIME_OMIT
    {
        struct timespec times[2];

#if defined OPTK_OS_MACOSX
        times[0] = sbuf.st_atimespec;
        times[1] = sbuf.st_mtimespec;
#else
        times[0] = sbuf.st_atim;
        times[1] = sbuf.st_mtim;
#endif
        if (utimensat(AT_FDCWD, dest_path, times, 0) != 0)
            return -1;
    }
#else  /* legacy utime */
    {
        struct utimbuf utbuf;

        utbuf.actime = sbuf.st_atime;
        utbuf.modtime = sbuf.st_mtime;
        if (utime(dest_path, &utbuf) != 0)
            return -1;
    }
#endif

The reason is on MacOSX 10.13 High Sierra, utimensat() exists and its times param expects nanosecond precision time from timespec's tv_nsec. The supplied patch assumes none of the MacOS versions have utimensat(), this is no longer true.