Very odd!
I just got my hammerfall working again, so I had time to devote to getting gem to build. I deleted my old gem-0.90.0 directory, downloaded a new copy and patched it with the patch supplied by (the very kind) Guenter Geiger: 00_buildsys.patch.gz
Unlike before, the patch installed without complaint! I must have accidently ran it aginst a version of the source that I had already tinkered with. Sorry Mr. Geiger.
I dont know what gem is configured with, as there were no options for ./configure --help. I hope ieee1394 is installed.
Anyway, it configured and built without complaint this time, for my AMD64 laptop and 2.6.9-rc3!
Now about zexy...
Thanks for the help Guenter Geiger! -thewade