Taken from Richard Drummond's website
: "This release fixes some bugs in the previous one, including a potential segfault in the keymap code at start-up and the broken Kickstart emulation. Also, the missing glue files for compiling against the SDL framework on OS X are now included in the source tarball, and memory usage at start-up in the OS4.0 version has been reduced. See the ChangeLog
for the full details."