Image optimizations

[MaxKellermann]

Quick benchmark of the OpenVario optimizations I made in the past weeks:

Version	Compressed image	rootfs	Cold boot to menu
20193	85 MB	194 MB	27.5s
2da58cb	43 MB	90 MB	12.5s
ed6ded5	38 MB	82 MB
experimental	33 MB	70 MB	10.5s

All optimizations were made without losing features.

My experimental build (last line) includes unfinished patches which I havn't yet submitted; some of the changes:

• no variod (I'd like to use XCSoar's audio vario instead)
• no PulseAudio (was only necessary for variod)
• sensord will also be removed (I'd like to integrate that into XCSoar as well)
• no connman (using systemd-networkd & wpa_supplicant instead)
• no ovmenu-ng (replaced with XCSoar-based menu)
• no bash (was only needed by ovmenu-ng)

[kedder]

Please keep connman!

[MaxKellermann]

I will not submit the connman-removal patch for merging until the new GUI menu has full support for wpa_supplicant.

If you wish to keep connman, declare a RDEPENDS (or better: RRECOMMENDS) on it from whatever package needs it; for example, your Python menu should have that dependency, because it's a frontend for connman. That way, those who install your menu will automatically have connman. But it makes no sense to make connman a top-level image dependency, because it image itself has no use for connman.

[kedder]

Users do use connman. It is part of the feature set. Just like everything else. You can just as well implement a full support of connman in your GUI menu for that matter.

[MaxKellermann]

No, I won't implement connman support, because connman is just an overly complex frontend for wpa_supplicant. Why talk to connman, when talking to wpa_supplicant is much simpler? I have a wpa_supplicant client + UI already, I just need to wire it into the OpenVarioMenu.