Support running ABCL on JamVM

[Mark Evenson]

A request to support ABCL running on the ​JamVM.

This may be roughly equivalent to working through the idiosyncrasies of running with ​GNU classpath, as GCJ seems to give similar errors.

[Mark Evenson]

The error reported produced on JamVM

Armed Bear Common Lisp 0.23.1
Java 1.5.0 GNU Classpath
JamVM
Low-level initialization completed in 0.844 seconds.
Exception in thread "interpreter" java.lang.IllegalStateException
   at java.nio.charset.CharsetEncoder.encode(CharsetEncoder.java:163)
   at org.armedbear.lisp.util.DecodingReader.unread(DecodingReader.java:173)
   at org.armedbear.lisp.util.DecodingReader.unread(DecodingReader.java:161)
   at org.armedbear.lisp.Stream._unreadChar(Stream.java:1719)
   at org.armedbear.lisp.Stream._readToken(Stream.java:1160)
   at org.armedbear.lisp.Stream.readToken(Stream.java:1026)
   at org.armedbear.lisp.Stream.processChar(Stream.java:521)
   at org.armedbear.lisp.Stream.readList(Stream.java:681)
   at org.armedbear.lisp.LispReader$3.execute(LispReader.java:88)
   at org.armedbear.lisp.Stream.processChar(Stream.java:514)
   at org.armedbear.lisp.Stream.readPreservingWhitespace(Stream.java:484)
   at org.armedbear.lisp.Stream.readPreservingWhitespace(Stream.java:492)
   at org.armedbear.lisp.Stream.read(Stream.java:430)
   at org.armedbear.lisp.Load.loadStream(Load.java:563)
   at org.armedbear.lisp.Load.loadFileFromStream(Load.java:535)
   at org.armedbear.lisp.Load.loadFileFromStream(Load.java:425)
   at org.armedbear.lisp.Load.loadSystemFile(Load.java:324)
   at org.armedbear.lisp.Interpreter.initializeLisp(Interpreter.java:163)
   at org.armedbear.lisp.Interpreter.createDefaultInstance(Interpreter.java:94)
   at org.armedbear.lisp.Main$1.run(Main.java:48)
   at java.lang.Thread.run(Thread.java:745)