[XM] Add the option to ignore missing files during registration

[alanmcgovern]

Not all assemblies referenced at compile time are necessary
at runtime. Allow XamMac to ignore missing assemblies just
like iOS does.

Fixes https://bugzilla.xamarin.com/show_bug.cgi?id=51746

[dnfclas]

Hi @alanmcgovern, I'm your friendly neighborhood .NET Foundation Pull Request Bot (You can call me DNFBOT). Thanks for your contribution!
You've already signed the contribution license agreement. Thanks!

The agreement was validated by .NET Foundation and real humans are currently evaluating your PR.

TTYL, DNFBOT;

[alanmcgovern]

/cc @chamons

[monojenkins]

Build failure

[spouliot]

Note that the comment on iOS is correct only for the simulator (JIT) and should be updated before merging (linking and AOT'ing impose restriction on missing code).

[alanmcgovern]

I wasn't sure what the implications are so i don't know how the comment should be updated. I just wanted to push a POC while they details are hammered out so I can investigate stripping out 20MB of files from our zip :)

[chamons]

🎉

[chamons]

I will fix the build failure.

[monojenkins]

Build success

[alanmcgovern]

I'll grab this build shortly and see how much junk I can strip out from our XVS integration now. Thanks! :D

[TonyValenti]

Hi @alanmcgovern and @chamons ,
I'm new to Xamarin / Visual Studio for Mac so if I'm posting in the wrong place, I'm sorry.

I'm using VS for Mac Preview #5 . When I go to Visual Studio >About Visual Studio > Show Details it shows:

Xamarin.Mac
Version: 3.0.0.393 (Visual Studio Enterprise)

How can I upgrade to the version that contains this fix? (it looks like it is xamarin-mac-3.2.0.20).

Thanks for your help!

[chamons]

@TonyValenti The standard place to discuss things like this is either the dev gitter:

https://gitter.im/xamarin/xamarin-macios

or the XM forums:

https://forums.xamarin.com/categories/mac

You are welcome to build everything by hand (https://github.com/xamarin/xamarin-macios/blob/master/README.md) but it can be non-trivial to setup and if you just want a recent build is unnecessary as they are published on Jenkins:

https://jenkins.mono-project.com/view/Xamarin.MaciOS/job/xamarin-macios-builds-master/