title: Make Ruby 1.9 regard all source files to be UTF-8 encoded. (Even if recompiling the interpreter is necessary)
body: <p>I want to port a rails app from Ruby 1.8.7 to 1.9.2. Some of the files contain umlauts like ä/ö/ü both within strings and comments.
  The files were saved as UTF-8 but without a <a href="http://en.wikipedia.org/wiki/Byte_order_mark" rel="noreferrer">BOM</a> (byte order mark) at the beginning. </p>
  
  <p>As you might know, <a href="http://ruby.runpaint.org/encoding#source" rel="noreferrer">Ruby 1.9 refuses to parse these files</a>, giving an <code>invalid multibyte char (US-ASCII)</code></p>
  
  <p>I was googling and reading a lot but the only solution to this seems to be to</p>
  
  <ul>
  <li>insert a BOM or</li>
  <li>insert <code># coding: utf-8</code></li>
  </ul>
  
  <p>at the beginning of <em>each</em> file.</p>
  
  <p>My editor of choice (gEdit) doesn't seem to insert a BOM. I also read that having a BOM is bad practice because it may break some editors, it also breaks shell scripts if you want to use the shebang notation.</p>
  
  <p><strong><em>EDIT</strong>: The BOM breaks the Ruby 1.8.7 parser, giving a <code>syntax error, unexpected kEND, expecting $end (SyntaxError)</code> for the file!</em> </p>
  
  <p>I tried forcing the external encoding with ruby -Eutf-8:utf-8 but this seems to be ignored when calling rake (I tried: /home/malte/.rvm/gems/ruby-1.9.2-p180/bin/rake test).</p>
  
  <p>So my question is:</p>
  
  <p>As RVM is building ruby 1.9 from source anyway, <strong>is there a build option or a patch to change the default encoding from US-ASCII to UTF-8</strong>?</p>
  
  <p>I took a quick look at the source code but couldn't find the line where the default is set (I'm no C expert, tough).</p>