Description: Use system Z3
 Dafny by default looks for its vendored Z3.  Modify it to look for the system
 Z3 installation instead.
Forwarded: not-needed
Author: Benjamin Barenblat <bbaren@mit.edu>
--- a/Source/Dafny/DafnyOptions.cs
+++ b/Source/Dafny/DafnyOptions.cs
@@ -283,29 +283,7 @@ namespace Microsoft.Dafny
     /// so we vendor a Windows version.
     /// </summary>
     private void SetZ3ExecutableName() {
-      var platform = (int)System.Environment.OSVersion.Platform;
-
-      // http://www.mono-project.com/docs/faq/technical/
-      var isUnix = platform == 4 || platform == 128;
-      
-      var z3binName = isUnix ? "z3" : "z3.exe";
-      var dafnyBinDir = System.IO.Path.GetDirectoryName(System.Reflection.Assembly.GetExecutingAssembly().Location);
-      var z3BinDir = System.IO.Path.Combine(dafnyBinDir, "z3", "bin");
-      var z3BinPath = System.IO.Path.Combine(z3BinDir, z3binName);
-
-      if (!System.IO.File.Exists(z3BinPath) && !isUnix) {
-        // This is most likely a Windows user running from source without downloading z3 
-        // separately; this is ok, since we vendor z3.exe.
-        z3BinPath = System.IO.Path.Combine(dafnyBinDir, z3binName);
-      }
-      
-      if (!System.IO.File.Exists(z3BinPath) && errorReporter != null) {
-        var tok = new Bpl.Token(1, 1) { filename = "*** " };
-        errorReporter.Warning(MessageSource.Other, tok, "Could not find '{0}' in '{1}'.{2}Downloading and extracting a Z3 distribution to Dafny's 'Binaries' folder would solve this issue; for now, we'll rely on Boogie to find Z3.", 
-          z3binName, z3BinDir, System.Environment.NewLine);
-      } else {
-        Z3ExecutablePath = z3BinPath;
-      }
+      Z3ExecutablePath = "/usr/bin/z3";
     }
 
     public override void Usage() {