sys-devel/bc-1.06-r5 compiles and runs with no problems in Panther.
Please add the macos keyword to portage.
>>> Completed installing into /var/tmp/portage/bc-1.06-r5/image/
* checking 11 files for package collisions
existing file /usr/bin/bc is not owned by this package
existing file /usr/bin/dc is not owned by this package
* spend 0.097815990448 seconds checking for file collisions
* This package is blocked because it wants to overwrite
* files belonging to other packages (see messages above).
In addition to the above, bc is already in package.provided. Might not be the latest version, but until someone wants to fix the later version for mac os x (I don't see why anyone would, but hey I'm not God), this bug will be marked WONTFIX.
Closing out bugs that've been resolved for a while now...