Revert pull request #427.

Reverts c811d87, 090a4ab, 253322a, and e86cc03, part of pull
request #427, in favor of resolving issue #473.

This removes the `CONFIG_START` and `CONFIG_END` macros in the hopes of
adding them again, after further testing, at a later date.

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This was a clean `git revert`, so once pull request #475 is ready for action it should be an easy merge. Before then, I think we should bump the version to 2.2.4 ASAP--failures on 64-bit ain't cool for most users.