zip better release

[tansy]

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It makes sense to compress release version the best possible as it is done only once and then decompressed many times over.
It also doesn't cost much - here, less than 0.25 s more during make.

[dirkf]

The default compression is -6 which gives a 12% smaller than -1 for 30% more time (against the current codebase).

The trade-off for -9 is x2 CPU vs 7% better compression. This example shows why -6 was set to be the default.

But as far as I can tell there's no reason why you couldn't use the higher, or any, compression level in your builds, since all Python versions that we support have a compatible zlib module.

[tansy]

On ancient computer:

$ time make -f Makefile youtube-dl

real    0m2.048s
user    0m1.426s
sys     0m0.539s

$ time make -f Makefile-zip-9 youtube-dl

real    0m2.128s
user    0m1.781s
sys     0m0.274s

difference in time is, literally, blink of an eye.

Even decompression is faster. Slightly but it is.

Overall gain is small, but the cost is even smaller. It's imperceptible.

--
I'd like to take this opportunity to ask why is 'executable' (`youtube-dl' pyexe) included in source package (youtube-dl.tar.gz)? It's already generated as executable and then included in source. I guess noone is using it as a source but still, the question remains.