Sdl backend (#670)

* [audio] added sdl audio backend and in-tree atrac9 decoder

* [input] replaced per-platform pad readers with sdl gamepad input

* [video] added sdl window and host display plumbing

* [gui] added host display options and per-game render settings

* [bink] synced host movie playback to the guest audio clock

* [cpu] hooked windows write faults into guest image tracking

* [perf] added guest and render profiling, reserved host cpu lanes

* [kernel] fixed stale pthread mutex handle alias

* [host] wired the sdl session, save-data paths and project references

* [audio] hoisted ajm trace stackalloc out of its loop

* [video] Add guest image sync setting

* [build] Strip native symbols

* reuse

src/SharpEmu.HLE/CpuContext.cs

@@ -20,6 +20,15 @@ public sealed class CpuContext(ICpuMemory memory, Generation generation)
 
     public ulong Rip { get; set; }
 
+    /// <summary>
+    /// Index of the import this context is currently executing, or -1 when it is
+    /// running guest code. Only maintained while guest profiling is enabled;
+    /// <see cref="Rip"/> alone cannot answer "what is this thread inside right
+    /// now" because it keeps pointing at the last import stub after the call
+    /// returns.
+    /// </summary>
+    public int ActiveImportIndex { get; set; } = -1;
+
     public ulong Rflags { get; set; }
 
     public ulong FsBase { get; set; }