Exclude the managed code around libproc on iOS/tvOS

src/libraries/System.Diagnostics.Process/src/System.Diagnostics.Process.csproj

@@ -311,17 +311,24 @@
   </ItemGroup>
   <ItemGroup Condition=" '$(TargetsOSX)' == 'true' or '$(TargetsiOS)' == 'true' or '$(TargetstvOS)' == 'true'">
     <Compile Include="System\Diagnostics\Process.BSD.cs" />
-    <Compile Include="System\Diagnostics\Process.OSX.cs" />
     <Compile Include="System\Diagnostics\ProcessManager.BSD.cs" />
-    <Compile Include="System\Diagnostics\ProcessManager.OSX.cs" />
-    <Compile Include="System\Diagnostics\ProcessThread.OSX.cs" />
-    <Compile Include="$(CommonPath)Interop\OSX\Interop.libproc.cs"
-             Link="Common\Interop\OSX\Interop.libproc.cs" />
     <Compile Include="$(CommonPath)Interop\OSX\Interop.libproc.GetProcessInfoById.cs"
              Link="Common\Interop\OSX\Interop.libproc.GetProcessInfoById.cs" />
     <Compile Include="$(CommonPath)Interop\OSX\Interop.Libraries.cs"
              Link="Common\Interop\OSX\Interop.Libraries.cs" />
   </ItemGroup>
+  <ItemGroup Condition="'$(TargetsOSX)' == 'true'">
+    <Compile Include="$(CommonPath)Interop\OSX\Interop.libproc.cs"
+             Link="Common\Interop\OSX\Interop.libproc.cs" />
+    <Compile Include="System\Diagnostics\Process.OSX.cs" />
+    <Compile Include="System\Diagnostics\ProcessManager.OSX.cs" />
+    <Compile Include="System\Diagnostics\ProcessThread.OSX.cs" />
+  </ItemGroup>
+  <ItemGroup Condition="'$(TargetsiOS)' == 'true' or '$(TargetstvOS)' == 'true'">
+    <Compile Include="System\Diagnostics\Process.iOS.cs" />
+    <Compile Include="System\Diagnostics\ProcessManager.iOS.cs" />
+    <Compile Include="System\Diagnostics\ProcessThread.iOS.cs" />
+  </ItemGroup>
   <ItemGroup Condition="'$(TargetsWindows)' == 'true'">
     <Compile Include="$(CommonPath)Interop\Windows\Shell32\Interop.ShellExecuteExW.cs"
              Link="Common\Interop\Windows\Shell32\Interop.ShellExecuteExW.cs" />

src/libraries/System.Diagnostics.Process/src/System/Diagnostics/Process.iOS.cs

@@ -0,0 +1,18 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Collections.Generic;
+using System.ComponentModel;
+
+namespace System.Diagnostics
+{
+    public partial class Process
+    {
+        public TimeSpan PrivilegedProcessorTime => throw new PlatformNotSupportedException();
+        public TimeSpan TotalProcessorTime => throw new PlatformNotSupportedException();
+        public TimeSpan UserProcessorTime => throw new PlatformNotSupportedException();
+        internal DateTime StartTimeCore => throw new PlatformNotSupportedException();
+        private int ParentProcessId => throw new PlatformNotSupportedException();
+        private string GetPathToOpenFile() => throw new PlatformNotSupportedException();
+    }
+}

src/libraries/System.Diagnostics.Process/src/System/Diagnostics/ProcessManager.iOS.cs

@@ -0,0 +1,27 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System.Collections.Generic;
+using System.IO;
+using System.Runtime.InteropServices;
+
+namespace System.Diagnostics
+{
+    internal static partial class ProcessManager
+    {
+        public static int[] GetProcessIds()
+        {
+            throw new PlatformNotSupportedException();
+        }
+
+        private static ProcessInfo CreateProcessInfo(int pid)
+        {
+            throw new PlatformNotSupportedException();
+        }
+
+        private static string GetProcPath(int processId)
+        {
+            throw new PlatformNotSupportedException();
+        }
+    }
+}

src/libraries/System.Diagnostics.Process/src/System/Diagnostics/ProcessThread.iOS.cs

@@ -0,0 +1,18 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace System.Diagnostics
+{
+    public partial class ProcessThread
+    {
+        public TimeSpan PrivilegedProcessorTime => throw new PlatformNotSupportedException();
+        public TimeSpan TotalProcessorTime => throw new PlatformNotSupportedException();
+        public TimeSpan UserProcessorTime => throw new PlatformNotSupportedException();
+        private ThreadPriorityLevel PriorityLevelCore
+        {
+            get { throw new PlatformNotSupportedException(SR.ThreadPriorityNotSupported); }
+            set { throw new PlatformNotSupportedException(SR.ThreadPriorityNotSupported); }
+        }
+        private DateTime GetStartTime() => throw new PlatformNotSupportedException();
+    }
+}