passing it through to OPEN.
** LOAD on source files likewise passes any EXTERNAL-FORMAT
argument given to internal calls to OPEN.
+ ** the built-in comment readers (introduced by character sequences
+ ";" and "#|") are more forgiving to encoding errors; they will
+ STYLE-WARN and then attempt to resync the stream at a character
+ boundary. (thanks to Teemu Kalvas)
* fixed some bugs revealed by Paul Dietz' test suite:
** Space, Tab, Linefeed, Return and Page have the invalid
secondary constituent character trait.