Loading of nested type of missing type needs to create another missing type. Fixes #12989
Update ast visitor
Update the Mono LLVM EH Frame reading code to match llvm 5f3329c6d97bb765dc54592367087d9ce8cd0040.
[xbuild] / [PCL]: Report an error for unsupported / missing PCL Profiles.

We previously only reported a warning, then failed later with tons of
"The predefined type `System.Object' is not defined or imported", which
was very confusing to the user.

We now distinguish between missing Reference Assemblies (ie. none of
them are installed) and the requested profile not being available, reporting
a meaningful error message.
Clean up preprocessor ifdefs in mono_thread_get_stack_bounds and fix the way thread stack information is retrieved on BSD

Cleaned up the heavily-nested preprocessor ifdefs. The code within the function was extremely difficult to understand because of the nested preprocessor directives, which has led to a number of avoidable configuration-related bugs. I've de-nested the ifdefs into a mostly-flat style, where we check for each platform just once and the entirety of the code for that platform falls under that single check. This improves the readability of the code and should fix the configuration-related issues on some platforms.

This code also fixes an issue where thread-stack information wasn't retrieved correctly on BSD-based systems; now the platform is detected correctly and the `pthread_attr_get_np` function used to retrieve the information.

This subsumes pull-request #553, which couldn't be merged with the current master branch due to several changes which were made to the `mono_thread_get_stack_bounds` function since that pull request was submitted. This commit also keeps the OpenBSD-related code for auditing purposes, though it may be removed later if testing shows the "generic" BSD handler works for OpenBSD.
Disable a failing System.Core test for mt (#12987).
Merge pull request #684 from jack-pappas/patch-7

Clean up preprocessor ifdefs in mono_thread_get_stack_bounds and fix the way thread stack information is retrieved on BSD
Interface members  are hidden by class members if a type parameter has an effective base other than object
Avoid passing class pointers to some marshal icalls since its not aot compatible. Fixes #12595.
Make synchronized wrappers of generic methods generic the same way it is done with delegate invokes.
Fix behavior of Console.Is*Redirected.

Setting Console.Out to a custom stream should not affect the value
of Console.IsOutputRedirected. This is how Microsoft's implementation
behaves.
Check expression type of resolved expressions too
Emit additional sequence points for call entry when needed. Fixes #10782 and similars
Correctly reset buffer for nested asynchronous file stream writes. Fixes #12777
Add IISVersion property to HttpRuntime
Merge pull request #687 from miniBill/master

Add IISVersion property to HttpRuntime
Fixes build
Added handling of 'targetFramework' attribute (new in .NET 4.5) to HttpRuntime and HttpRuntimeSection
Merge pull request #690 from akoeplinger/httpruntime-net45

Added handling of 'targetFramework' attribute to HttpRuntime
Remove some gcc-ism from mono_atomic_load_acquire/release, so it can be compiled by msvc.