C#: Re-direct std error.

Author: michaelnebel

csharp/extractor/Semmle.Util/BuildActions.cs

@@ -198,7 +198,8 @@ private static ProcessStartInfo GetProcessStartInfo(string exe, string arguments
             var pi = new ProcessStartInfo(exe, arguments)
             {
                 UseShellExecute = false,
-                RedirectStandardOutput = true
+                RedirectStandardOutput = true,
+                RedirectStandardError = true
             };
             if (workingDirectory is not null)
                 pi.WorkingDirectory = workingDirectory;
@@ -219,13 +220,13 @@ int IBuildActions.RunProcess(string exe, string args, string? workingDirectory,
         int IBuildActions.RunProcess(string cmd, string args, string? workingDirectory, IDictionary<string, string>? environment)
         {
             var pi = GetProcessStartInfo(cmd, args, workingDirectory, environment);
-            return pi.ReadOutput(out _, onOut: Console.WriteLine, onError: null);
+            return pi.ReadOutput(out _, onOut: Console.WriteLine, onError: Console.WriteLine);
         }
 
         int IBuildActions.RunProcess(string cmd, string args, string? workingDirectory, IDictionary<string, string>? environment, out IList<string> stdOut)
         {
             var pi = GetProcessStartInfo(cmd, args, workingDirectory, environment);
-            return pi.ReadOutput(out stdOut, onOut: null, onError: null);
+            return pi.ReadOutput(out stdOut, onOut: Console.WriteLine, onError: Console.WriteLine);
         }
 
         void IBuildActions.DirectoryDelete(string dir, bool recursive) => Directory.Delete(dir, recursive);