coreclr mscorlib integration

[xen2]

I have been playing out with coreclr mscorlib since it came out a few weeks ago.

Here is current integration plan:

1. Start a coreclr branch with src/mcs filtered out (history rewrite, to reduce repository size). From now on, SharpLang will only contain compiler, runtime and mscorlib only (no other C# library -- corefx and/or Mono src/mcs/class can be used to get them). Objective is to keep this repository and build lightweight.
2. Include src/mscorlib from coreclr (using git subtree)
3. Add necessary changes so that codegen unit tests are working. Note: mscorlib unit test is working for WriteLine, but more advanced require the C++ runtime bits.
4. Reuse coreclr C++ code to work with SharpLang, to provide native implementation of everything necessary for full mscorlib to run. I have made good progress on a prototype and it seems like a good way to go. It will be done by using as many source files untouched, and replacing the various parts that needs to.
5. As soon as everything is stabilized, coreclr becomes the new master (note: force push due to history rewrite happening in 1).
6. Integrate GC from corlib.

2 and 3 are already done, 4 is prototyped.

I will start pushing changes over the next few days.

[xen2]

Steps 1, 2 and 3 are done.
Codegen unit tests and real mscorlib WriteLine unit test are working!

[xen2]

Currently switching to CMake for easier integration of Linux CoreCLR PAL.

[xen2]

SharpLang compiler is still built using premake (only solution to easily support C++ and C# together).

However, runtime is now built with CMake. On Linux, it also includes PAL from CoreCLR.

[amerkoleci]

Cmake has the include_external_msproject command for adding C# projects

[xen2]

According to doc, "Currently does nothing on UNIX."