This is a smaller, cheaper, faster SED implementation. Minix uses it. GNU
used to use it, until they built their own sed around an extended (some
would say over-extended) regexp package.

For embedded use we searched for a tiny sed implementation especially for
use with the dietlibc and found Eric S. Raymond's sed implementation quite
handy. Though it suffered several bugs and was not under active maintenance
anymore. After sending a bunch of fixes we agreed to continue maintaining
this lovely, historic sed implementation.

Along with a lot fixes and cleanups, further speedups, and some missing
features and POSIX conformance, we also added a test-suite to the package,
so regressions are quickly and easily uncovered.