I now distribute my own modifications to Spidermonkey with the project. This allows you to easily compile it with my preferred modifications. If you want to see what modifications I make, read the INSTALL.spidermonkey or INSTALL.spidermonkey.shellcode files.
You can now get the source code for the project from https://code.google.com/p/jsunpack-n/ (instead of my website).
Updates 2010-05-20 version 0.3.2b
1) added INSTALL.spidermonkey.shellcode instructions. This adds improved shellcode detection.
2) updated jsunpack class options structure. New options will always use file contents instead of filenames (where possible). Also, rules are now part of the options structure.
3) socket defaulttimeout now part of jsunpack class (it was global before). If you import jsunpack, make sure to set a timeout on your own.
4) you can use jsunpack.version to get the current version string
5) new performance option (-f "fasteval") for disabling non-critical features in favor of performance
6) fixed a bug in redoevaltime option affecting performance of malicious scripts
7) fixed a pdf parsing bug for /Page related to testcase samples/pdf-numPages.file