Use the list of prerequisites instead of listing those files manually,
this way they will never fall out of sync.
Also update the amalgamation example to use a single cat command.
Fixes: a7e8d394 ("[amalgamation] add test")
Fixes: b192c86b ("[amalgamation] lz4frame.c")
make it possible to generate LZ4-compressed block
with a controlled maximum offset (necessarily <= 65535).
This could be useful for compatibility with decoders
using a very limited memory budget (<64 KB).
Answer #154
Having a dedicated file for optimal parser
made sense during its creation,
it allowed Przemyslaw to work more freely on lz4opt, with less dependency on lz4hc,
moreover, the optimal parser was more complex, with its own search functions.
Since the optimal was rewritten last year, it's now a lot lighter.
It makes more sense now to integrate it directly inside lz4hc.c,
making it easier to edit (editors are a bit "lost" inside a `*.h` dependent on its #include position),
it also reduces the number of files in the project,
which fits pretty well with lz4 objectives.
(adding lz4hc requires "just" lz4hc.h and lz4hc.c).
