ECONV_NEWLINE_DECORATOR_WRITE_MASK): new macro.
* io.c (rb_io_extract_modeenc, pipe_open, prep_stdio, argf_next_argv):
set TEXTMODE_NEWLINE_DECORATOR_ON_WRITE for textmode on creating IO
if the flag is available.
* io.c (make_writeconv): drop decorators for reading.
* io.c (make_readconv): drop decorators for writing.
* io.c (do_writeconv): existing writeconv is not the condition to raise
ArgumentError. should check textmode or not.
* test/ruby/test_io_m17n.rb
(TestIO_M17N#test_{cr,lf,crlf}_decorator_on_stdout): test above
changes.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@33662 b2dd03c8-39d4-4d8f-98ff-823fe69b080e