bsd-port merged up

[Alexander Strange]

I've merged the new changes in from bsd-port.

Hotspot has added a new feature allowing it to print symbol names in the native code parts of crash backtraces. This uses an ELF reader, and doesn't work on Mac OS X, which doesn't use ELF.

If you happen to be debugging, you can use gdb; 'bt' gives a native backtrace and 'call ps()' gives a Java backtrace of the current thread. ps() and pss() are usually only available in debugging hotspot, but are available in product (default) builds as well in macosx-port.