Provide .NET 4.6.1 framework target

LibGit2Sharp.Tests/LibGit2Sharp.Tests.csproj

@@ -28,7 +28,6 @@
   <Target Name="CopyTestAppExes" AfterTargets="ResolveProjectReferences">
     <ItemGroup>
       <_TestAppFile Include="@(TestAppExe->'%(RootDir)%(Directory)%(Filename).exe')" />
-      <_TestAppFile Include="@(TestAppExe->'%(RootDir)%(Directory)%(Filename).exe.config')" />
       <_TestAppFile Include="@(TestAppExe->'%(RootDir)%(Directory)%(Filename).pdb')" />
     </ItemGroup>
 

LibGit2Sharp/Core/NativeMethods.cs

@@ -37,7 +37,11 @@ static NativeMethods()
                     // Try to load the .dll from the path explicitly.
                     // If this call succeeds further DllImports will find the library loaded and not attempt to load it again.
                     // If it fails the next DllImport will load the library from safe directories.
+#if NETFRAMEWORK
+                    if (Platform.OperatingSystem == OperatingSystemType.Windows)
+#else
                     if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+#endif
                     {
                         LoadWindowsLibrary(nativeLibraryPath);
                     }

LibGit2Sharp/Core/Platform.cs

@@ -13,11 +13,30 @@ internal enum OperatingSystemType
     internal static class Platform
     {
         public static string ProcessorArchitecture => IntPtr.Size == 8 ? "x64" : "x86";
+#if NETFRAMEWORK 
+        private static bool? _isRunningOnMac;
+        private static bool IsRunningOnMac() => _isRunningOnMac ?? (_isRunningOnMac = TryGetIsRunningOnMac()) ?? false;
+#endif
 
         public static OperatingSystemType OperatingSystem
         {
             get
             {
+#if NETFRAMEWORK
+                var platform = (int)Environment.OSVersion.Platform;
+                if (platform <= 3 || platform == 5)
+                {
+                    return OperatingSystemType.Windows;
+                }
+                if (IsRunningOnMac())
+                {
+                    return OperatingSystemType.MacOSX;
+                }
+                if (platform == 4 || platform == 6 || platform == 128)
+                {
+                    return OperatingSystemType.Unix;
+                }
+#else
                 if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
                 {
                     return OperatingSystemType.Windows;
@@ -32,7 +51,7 @@ public static OperatingSystemType OperatingSystem
                 {
                     return OperatingSystemType.MacOSX;
                 }
-
+#endif
                 throw new PlatformNotSupportedException();
             }
         }
@@ -71,5 +90,70 @@ public static bool IsRunningOnNetFramework()
         /// </summary>
         public static bool IsRunningOnNetCore()
             => typeof(object).Assembly.GetName().Name != "mscorlib";
+
+#if NETFRAMEWORK
+#pragma warning disable IDE1006 // Naming Styles
+        [DllImport("libc")]
+        private static extern int sysctlbyname(
+            [MarshalAs(UnmanagedType.LPStr)] string property,
+            IntPtr output,
+            IntPtr oldLen,
+            IntPtr newp,
+            uint newlen);
+#pragma warning restore IDE1006 // Naming Styles
+
+        private static bool TryGetIsRunningOnMac()
+        {
+            const string OsType = "kern.ostype";
+            const string MacOsType = "Darwin";
+
+            return MacOsType == GetOsType();
+
+            string GetOsType()
+            {
+                try
+                {
+                    IntPtr
+                        pointerLength = IntPtr.Zero,
+                        pointerString = IntPtr.Zero;
+
+                    try
+                    {
+                        pointerLength = Marshal.AllocHGlobal(sizeof(int));
+
+                        sysctlbyname(OsType, IntPtr.Zero, pointerLength, IntPtr.Zero, 0);
+
+                        var length = Marshal.ReadInt32(pointerLength);
+
+                        if (length <= 0)
+                        {
+                            return string.Empty;
+                        }
+
+                        pointerString = Marshal.AllocHGlobal(length);
+
+                        sysctlbyname(OsType, pointerString, pointerLength, IntPtr.Zero, 0);
+
+                        return Marshal.PtrToStringAnsi(pointerString);
+                    }
+                    finally
+                    {
+                        if (pointerLength != IntPtr.Zero)
+                        {
+                            Marshal.FreeHGlobal(pointerLength);
+                        }
+                        if (pointerString != IntPtr.Zero)
+                        {
+                            Marshal.FreeHGlobal(pointerString);
+                        }
+                    }
+                }
+                catch
+                {
+                    return null;
+                }
+            }
+        }
+#endif
     }
 }

LibGit2Sharp/LibGit2Sharp.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>netstandard2.0</TargetFramework>
+    <TargetFrameworks>netstandard2.0;net461</TargetFrameworks>
     <GenerateDocumentationFile>true</GenerateDocumentationFile>
     <Description>LibGit2Sharp brings all the might and speed of libgit2, a native Git implementation, to the managed world of .Net and Mono.</Description>
     <Company>LibGit2Sharp contributors</Company>
@@ -29,7 +29,7 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="LibGit2Sharp.NativeBinaries" Version="[1.0.226]" PrivateAssets="none" />
+    <PackageReference Include="LibGit2Sharp.NativeBinaries" Version="[1.0.233]" PrivateAssets="none" />
     <PackageReference Include="Microsoft.SourceLink.GitHub" Version="1.0.0-beta-63127-02" PrivateAssets="all" />
     <PackageReference Include="Nerdbank.GitVersioning" Version="2.2.13" PrivateAssets="all" />
   </ItemGroup>