[Client] [WSL] Extend detection.

[AenBleidd]

Move WSL detection to get_host_info().
Enumerate available WSLs from registry.
Add wslapi library loading.
Add support of multiple installed wsl distros detection.
Detect only installed and configured distros.
Add extra information parse.
Add wslinfo files to save and parse wsl info.
Add dont_use_wsl param to cc_config.
Add missed hostinfo_wsl.cpp when building win client using gcc.
Fix small issues.
Small refactoring.

Signed-off-by: Vitalii Koshura lestat.de.lionkur@gmail.com

[AenBleidd]

@davidpanderson, @ChristianBeer, @RichardHaselgrove, @JuhaSointusalo, @TheAspens
Guys, I encourage you to review this. I understand, that this is quite a big piece of code. But there was no way for me to make it less without losing some functionality :)

[JuhaSointusalo]

It seems that you are setting XML tag name from distro name. That's interesting idea but possibly bad one if you ever want to process the XML with something other than BOINC's XML parser. I would have the distro name in it's own element, say distro_name, and a constant name for the enclosing element, like distro or something.

[AenBleidd]

@JuhaSointusalo, ok, I'll fix this

[AenBleidd]

Fixed

[davidpanderson]

This all looks fine to me, though I'm unable to test it.

[AenBleidd]

wslconfig output:

boinc output:

client_state.xml:

[davidpanderson]

Looks good. I'll merge. Thanks for doing this.

[RichardHaselgrove]

Now we have a merged version, I was able to build a test version (VS 2013) and try it. No errors, and

27/06/2018 17:17:04 |  | WSL detected:
27/06/2018 17:17:04 |  | [Ubuntu] (default): Linux Ubuntu (Ubuntu 16.04.4 LTS [4.4.0-17134-Microsoft])

Unfortunately, I think GPUGrid have (temporarily?) abandoned their attempts to get Quantum Chemistry running under WSL, so full testing will have to wait. But good so far.

And under Windows 7, it simply says
27/06/2018 17:35:07 | | No WSL found.
I think that's good enough.

[RichardHaselgrove]

@AenBleidd: small bug

Running the WSL-enabled client under Windows 7, so no WSL available and none detected - all good.

Client writes extra line into cc_config.xml
<dont_use_wsl>0</dont_use_wsl>
but on reading config files after setting Event Log options or from menu, Event Log reports
29/06/2018 15:59:47 | | Unrecognized tag in cc_config.xml: <dont_use_wsl>

Patch in #2581