When ghostscript combines PDFs, how do I get it to NOT put boxes around links?

I am using ghostscript (gs) from the c开发者_如何学编程ommand line to combine mulitple PDFs into one PDF. It works great, except everywhere one of the PDFs has a link in it, it changes the link from an underscore to a box. There must be some argument I can pass in the call to gs that will get it to use underscores, or just to preserve links as per the original file. Does anyone know how?

Thank you.

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Found the answer - use the latest Ghostscript! I was using 8.15.2 before. Just downloaded and built 9.01 and it does not exhibit the problem.