Add NCE code

src/Ryujinx.Cpu/Nce/NceThreadPalAndroid.cs

@@ -0,0 +1,20 @@
+using System;
+using System.Runtime.InteropServices;
+
+namespace Ryujinx.Cpu.Nce
+{
+    static class NceThreadPalAndroid
+    {
+        [DllImport("libc", SetLastError = true)]
+        private static extern int pthread_kill(IntPtr thread, int sig);
+
+        public static void SuspendThread(IntPtr handle)
+        {
+            int result = pthread_kill(handle, NceThreadPal.UnixSuspendSignal);
+            if (result != 0)
+            {
+                throw new Exception($"Thread kill returned error 0x{result:X}.");
+            }
+        }
+    }
+}