Compile warning with mingw ("__stat64" redefined)

[Christian Biesinger]

Hello,

this is pretty minor, but I did notice this warning during the compile
of gnulib:
../../../gnulib/import/glob.c:75: warning: "__stat64" redefined
 # define __stat64(fname, buf)   stat (fname, buf)

In file included from /usr/share/mingw-w64/include/sys/stat.h:58,
                 from ./sys/stat.h:47,
                 from ./glob.h:551,
                 from ../../../gnulib/import/glob.c:28:
/usr/share/mingw-w64/include/_mingw_stat64.h:97: note: this is the
location of the previous definition
 #define __stat64 _stat64

This is using 8.3-win32 20190406 (GCC) as a crosscompiler from Debian to mingw.

May be good to fix, should require just an #undef, I would think.

I assume this is the gnulib module but just in case, these are all the
enabled modules:
IMPORTED_GNULIB_MODULES="\
    alloca \
    canonicalize-lgpl \
    dirent \
    dirfd \
    errno \
    fnmatch-gnu \
    frexpl \
    getcwd \
    glob \
    inet_ntop
    inttypes \
    lstat \
    limits-h \
    memchr \
    memmem \
    mkdir \
    mkdtemp \
    mkostemp \
    pathmax \
    rawmemchr \
    readlink \
    rename \
    setenv \
    signal-h \
    strchrnul \
    strerror_r-posix \
    strstr \
    strtok_r \
    sys_stat \
    time_r \
    unistd \
    unsetenv \
    update-copyright \
    wchar \
    wctype-h \
"


Christian