Apparently the [example on erlang.org](https://erlang.org/doc/tutorial/erl_interface.html)
is wrong for specific lengths of packets...

Originally by @kleidukos on evadne/gen_magic#11

This commit simplifies and fixes several quirks of the Makefile:

* LDLIBS is now used instead of LDFLAGS
* Only one step is now necessary to compile the binary
* clean is now marked as a PHONY rule

- History for v0.20.83 and previous versions is moved to archive/v0.20.83