brace the fact that lchmod(2) can EOPNOTSUPP

	Musl libc has this function as a tiny wrapper of fchmodat(3posix).  On
	the other hand Linux kernel does not support changing modes of a symlink.
	The operation always fails with EOPNOTSUPP.  This fchmodat behaviour is
	defined in POSIX.  We have to take care of such exceptions.

https://github.com/ruby/fileutils/commit/da15e3ce06

  This reverts commit eab88d20eaa925d5e61a2a65820a099b46ccf3f8.

  The some CI was broken with this.

https://github.com/ruby/fileutils/commit/f92145b10b

`FileUtils#install` methed raises an unexpected `TypeError`, when
called with `mode:` option which has `"X"`.

```
$ ruby -rfileutils -e 'FileUtils.install("tmp/a", "tmp/b", mode: "o+X")'
/opt/local/lib/ruby/2.7.0/fileutils.rb:942:in `directory?': no implicit conversion of File::Stat into String (TypeError)
	from /opt/local/lib/ruby/2.7.0/fileutils.rb:942:in `block (3 levels) in symbolic_modes_to_i'
	from /opt/local/lib/ruby/2.7.0/fileutils.rb:933:in `each_char'
	from /opt/local/lib/ruby/2.7.0/fileutils.rb:933:in `each'
	from /opt/local/lib/ruby/2.7.0/fileutils.rb:933:in `inject'
	from /opt/local/lib/ruby/2.7.0/fileutils.rb:933:in `block (2 levels) in symbolic_modes_to_i'
	from /opt/local/lib/ruby/2.7.0/fileutils.rb:931:in `each'
	from /opt/local/lib/ruby/2.7.0/fileutils.rb:931:in `each_slice'
	from /opt/local/lib/ruby/2.7.0/fileutils.rb:931:in `block in symbolic_modes_to_i'
	from /opt/local/lib/ruby/2.7.0/fileutils.rb:926:in `each'
	from /opt/local/lib/ruby/2.7.0/fileutils.rb:926:in `inject'
	from /opt/local/lib/ruby/2.7.0/fileutils.rb:926:in `symbolic_modes_to_i'
	from /opt/local/lib/ruby/2.7.0/fileutils.rb:973:in `fu_mode'
	from /opt/local/lib/ruby/2.7.0/fileutils.rb:883:in `block in install'
	from /opt/local/lib/ruby/2.7.0/fileutils.rb:1588:in `block in fu_each_src_dest'
	from /opt/local/lib/ruby/2.7.0/fileutils.rb:1604:in `fu_each_src_dest0'
	from /opt/local/lib/ruby/2.7.0/fileutils.rb:1586:in `fu_each_src_dest'
	from /opt/local/lib/ruby/2.7.0/fileutils.rb:877:in `install'
	from -e:1:in `<main>'
```

In spite of that `symbolic_modes_to_i` considers the `File::Stat`
`path` case at the beginning, in `"X"` case, `path` is passed to
`FileTest.directory?` method which requires a `String`.  In such
case, the mode in `path` should be examined instead.

https://github.com/ruby/fileutils/commit/2ea54ade2f

Loading separate version.rb unnecessary increases every start-up
time.  In the other hand, the gemspec file is parsed only when
building the gem file.

https://github.com/ruby/fileutils/commit/8359cf7cce

https://github.com/ruby/fileutils/commit/5ac9a8a1f7

https://github.com/ruby/fileutils/commit/ba81f024cf

Previously this would copy the symlink root as a symlink instead
of creating a new root directory.  This modifies the source
to expand it using File.realpath before starting the copy.

Fixes Ruby Bug 12123

https://github.com/ruby/fileutils/commit/7359cef359

If FileUtils is included into another object, and verbose mode is
used, a FrozenError is currently raised unless the object has the
@fileutils_output and @fileutils_label instance variables.

This fixes things so that it does not attempt to set the instance
variables, but it still uses them if they are present.

https://github.com/ruby/fileutils/commit/689cb9c56a