Add CSharpProjectProcessor to CompilerPlugin

Author: veblush

extra/CompilerPlugin.Unity4/CompilerPlugin.Unity4.csproj

@@ -47,6 +47,9 @@
     <Compile Include="..\CompilerPlugin\CSharp60SupportActivator.cs">
       <Link>CSharp60SupportActivator.cs</Link>
     </Compile>
+    <Compile Include="..\CompilerPlugin\CSharpProjectProcessor.cs">
+      <Link>CSharpProjectProcessor.cs</Link>
+    </Compile>
     <Compile Include="..\CompilerPlugin\CustomCSharpCompiler.cs">
       <Link>CustomCSharpCompiler.cs</Link>
     </Compile>

extra/CompilerPlugin.Unity5/CompilerPlugin.Unity5.csproj

@@ -48,6 +48,9 @@
     <Compile Include="..\CompilerPlugin\CSharp60SupportActivator.cs">
       <Link>CSharp60SupportActivator.cs</Link>
     </Compile>
+    <Compile Include="..\CompilerPlugin\CSharpProjectProcessor.cs">
+      <Link>CSharpProjectProcessor.cs</Link>
+    </Compile>
     <Compile Include="..\CompilerPlugin\CustomCSharpCompiler.cs">
       <Link>CustomCSharpCompiler.cs</Link>
     </Compile>

extra/CompilerPlugin/CSharpProjectProcessor.cs

@@ -0,0 +1,26 @@
+using System.IO;
+using System.Linq;
+using UnityEditor;
+
+public class CSharpProjectProcessor : AssetPostprocessor
+{
+	private static bool OnPreGeneratingCSProjectFiles()
+	{
+		var currentDirectory = Directory.GetCurrentDirectory();
+		var projectFiles = Directory.GetFiles(currentDirectory, "*.csproj");
+
+		foreach (var file in projectFiles)
+		{
+			UpdateProjectFile(file);
+		}
+
+		return false;
+	}
+
+	private static void UpdateProjectFile(string file)
+	{
+		var lines = File.ReadAllLines(file);
+		lines = lines.Where(line => line.Contains("LangVersion") == false).ToArray();
+		File.WriteAllLines(file, lines);
+	}
+}