clean autogenerated files

	* enc/depend (clean, clean-srcs): fix path of name2ctype.h, and
	  remove casefold.h too.

	* enc/jis/props.h: autogenerated file.
	  [ruby-core:80823] [Bug #13493]

	use $(srcdir).

	* Makefile.in (enc/jis/props.h): build it in not builddir, but in srcdir.


	Ignore enc/jis/props.h

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_4@62862 b2dd03c8-39d4-4d8f-98ff-823fe69b080e