[mkbundle] do not require dos2unix (and sh) on Windows. Skip it if it…

… does not exist.

mcs/tools/mkbundle/mkbundle.cs

@@ -37,6 +37,7 @@ class MakeBundle {
 	static string style = "linux";
 	static bool compress;
 	static bool nomain;
+	static bool? use_dos2unix = null;
 
 	static int Main (string [] args)
 	{
@@ -667,11 +668,42 @@ static int Execute (string cmdLine)
 			Console.WriteLine (cmdLine);
 			return system (cmdLine);
 		}
-
+		
 		// on Windows, we have to pipe the output of a
 		// `cmd` interpolation to dos2unix, because the shell does not
 		// strip the CRLFs generated by the native pkg-config distributed
 		// with Mono.
+		//
+		// But if it's *not* on cygwin, just skip it.
+
+		// check if dos2unix is applicable.
+		if (use_dos2unix == null) {
+			use_dos2unix = false;
+			try {
+				var dos2unix = Process.Start ("dos2unix");
+				dos2unix.StandardInput.WriteLine ("aaa");
+				dos2unix.StandardInput.WriteLine ("\u0004");
+				dos2unix.WaitForExit ();
+				if (dos2unix.ExitCode == 0)
+					use_dos2unix = true;
+			} catch {
+				// ignore
+			}
+		}
+		// and if there is no dos2unix, just run cmd /c.
+		if (use_dos2unix == false) {
+			Console.WriteLine (cmdLine);
+			ProcessStartInfo dos2unix = new ProcessStartInfo ();
+			dos2unix.UseShellExecute = false;
+			dos2unix.FileName = "cmd";
+			dos2unix.Arguments = String.Format ("/c \"{0}\"", cmdLine);
+
+			using (Process p = Process.Start (dos2unix)) {
+				p.WaitForExit ();
+				return p.ExitCode;
+			}
+		}
+
 		StringBuilder b = new StringBuilder ();
 		int count = 0;
 		for (int i = 0; i < cmdLine.Length; i++) {