If the file argument is a symbolic link, it will resolve the
symbolic link and use the file
referenced by the link.
static VALUE
rb_file_file_p(VALUE obj, VALUE fname)
{
struct stat st;
if (rb_stat(fname, &st) < 0) return Qfalse;
if (S_ISREG(st.st_mode)) return Qtrue;
return Qfalse;
}