Unable to compress when 'char' is present

[yurydelendik]

The minification of the following file fails:

function ord(char) {
  return char.charCodeAt(0);
}

$ java -jar ./build/yuicompressor-2.4.8.jar t.js
[ERROR] in t.js
  1:18:missing formal parameter
[ERROR] in t.js
  1:0:Compilation produced 1 syntax errors.
org.mozilla.javascript.EvaluatorException: Compilation produced 1 syntax errors.
    at com.yahoo.platform.yui.compressor.YUICompressor$1.runtimeError(YUICompressor.java:184)
    at org.mozilla.javascript.Parser.parse(Parser.java:396)
    at org.mozilla.javascript.Parser.parse(Parser.java:340)
    at com.yahoo.platform.yui.compressor.JavaScriptCompressor.parse(JavaScriptCompressor.java:315)
    at com.yahoo.platform.yui.compressor.JavaScriptCompressor.<init>(JavaScriptCompressor.java:536)
    at com.yahoo.platform.yui.compressor.YUICompressor.main(YUICompressor.java:159)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at com.yahoo.platform.yui.compressor.Bootstrap.main(Bootstrap.java:21)

The file is valid from the ECMAScript 5.1 point of view (see https://github.com/mozilla/pdf.js/issues/4547). Could you introduce an options to take ECMAScript 5 standard into account?

/cc @mschipperheyn

[tml]

Duplicate of #98