The current code reserves 60 bytes for the symbol string of every
exported symbol, unnecessarily wasting kernel memory since most symbols
are much shorter. We revert to the 2.4 solution where the actual strings
are saved out of line and only the pointers are kept.

The latest module-init-tools already handle this case, people who are
using older versions need to update to make sure depmod works
properly.

Saves 80 KB in vmlinux with my .config.