Fixing how we loog for clang so that it works on Linux

makefile.shade

@@ -154,13 +154,13 @@ functions @{
 
         foreach(var dir in Environment.GetEnvironmentVariable("PATH").Split(Path.PathSeparator))
         {
-            if (File.Exists(Path.Combine(dir, "clang")))
+            if (File.Exists(Path.Combine(dir, "clang++")))
             {
-                return Path.Combine(dir, "clang");
+                return Path.Combine(dir, "clang++");
             }
-            else if (File.Exists(Path.Combine(dir, "clang")))
+            else if (File.Exists(Path.Combine(dir, "clang++-3.5")))
             {
-                return Path.Combine(dir, "clang");
+                return Path.Combine(dir, "clang++-3.5");
             }
         }