This reverts commit ad9a80da.

Conflicts:
	mono/mini/mini.c

Reorganize the way jump_target_hash is stored in the JIT. Free entries in jump_target_hash which point inside a dynamic method when it is freed. Fixes #669815.

Ios/fix aot class leak

Map SO_EXCLUSIVEADDRUSE to !SO_REUSEADDR

	This will make windows app that use that property work on *nix.
	Fixes bug #643475.

Conflicts:
	external/buildscripts/build_runtime_android.sh

Windows Registry: fixed the issue when Microsoft.Win32.Registry.GetValue() required write permissions

(cherry picked from commit 70fe346b)

do not try to find manage frames when stepping out from either, last managed frame or frame in between managed/native ones (fix case #573949)

added bit field on MonoClass to indicate if the class has an IntPtr pointing to a native class that needs AssetGarbageCollection scanning

Conflicts:
	msvc/mono.def
	unity/unity_liveness.c

On my (cursed?) MacBook Pro, calling
System.Net.NetworkInformation.NetworkInterface.GetAllNetworkInterfaces()
results in an exception:

	System.ArgumentException: length
		at System.Array.Copy (System.Array sourceArray, Int32 sourceIndex, System.Array destinationArray, Int32 destinationIndex, Int32 length) [0x00000] in <filename unknown>:0
		at System.Net.NetworkInformation.MacOsNetworkInterface.ImplGetAllNetworkInterfaces () [0x00000] in <filename unknown>:0
		at System.Net.NetworkInformation.NetworkInterface.GetAllNetworkInterfaces () [0x00000] in <filename unknown>:0

Some printfs later, and we see why:

	Array.Copy(array.Length=12, 3, array.Length=0, 0, 0)
	Array.Copy(array.Length=12, 4, array.Length=0, 0, 0)
	Array.Copy(array.Length=12, 4, array.Length=0, 0, 0)
	Array.Copy(array.Length=12, 3, array.Length=6, 0, 6)
	Array.Copy(array.Length=12, 3, array.Length=6, 0, 6)
	Array.Copy(array.Length=12, 3, array.Length=8, 0, 4)
	Array.Copy(array.Length=12, 4, array.Length=6, 0, 6)
	Array.Copy(array.Length=12, 8, array.Length=6, 0, 6)
	# BOOM!

(Apparently I have 8 interfaces: lo0, gif0, stf0, en0, en1, fw0, p2p0,
and vboxnet0.)

The problem is readily obvious: we're trying to read 6 bytes of data
when only 4 are available, and Array.Copy() complains appropriately.

The fix -- which looks to almost contradict a02076ba -- is to use
`sockaddrdl.sdl_data.Length - sockaddrdl.sdl_nlen` instead of
`sockaddrdl.sdl_data.Length - macAddress.Length` (or sdl_alen).
sdl_nlen is the offset into the source sockaddrdl.sdl_data array, and
in this case sockaddrdl.sdl_alen (the length of the destination
macAddress) isn't the same as sockaddrdl.sdl_nlen, hence the breakage.

Conflicts:
	mcs/class/System/System.Net.NetworkInformation/NetworkInterface.cs

Fix iOS crosscompiler crash on Windows when --debug is specified.

By wrapping sigaction we make sure to always install a signal handler compiled for thumb.
The source code for the signal handler can be found here:
https://github.com/Unity-Technologies/krait-signal-handler

Fix iOS crosscompilation issues on Windows.