diff -ru cmake-2.8.6.old//Source/cmAddLibraryCommand.cxx cmake-2.8.6-nosourcelib/Source/cmAddLibraryCommand.cxx
--- cmake-2.8.6.old//Source/cmAddLibraryCommand.cxx	2011-10-04 18:09:24.000000000 +0200
+++ cmake-2.8.6-nosourcelib/Source/cmAddLibraryCommand.cxx	2011-11-04 16:38:20.680544736 +0100
@@ -31,6 +31,7 @@
     }
   bool excludeFromAll = false;
   bool importTarget = false;
+  bool noSourceFiles = false; 
 
   std::vector<std::string>::const_iterator s = args.begin();
 
@@ -79,6 +80,11 @@
       ++s;
       importTarget = true;
       }
+    else if(*s == "NO_SOURCE_FILES")
+      {
+      ++s;
+      noSourceFiles = true;
+      }
     else
       {
       break;
@@ -148,12 +154,13 @@
     }
   }
 
-  if (s == args.end())
+  if (s == args.end() && !noSourceFiles)
     {
     std::string msg = "You have called ADD_LIBRARY for library ";
     msg += args[0];
-    msg += " without any source files. This typically indicates a problem ";
-    msg += "with your CMakeLists.txt file";
+    msg += " without any source files. If this is what you want you";
+    msg += " should add the flag NO_SOURCE_FILES. Otherwise this may"; 
+    msg += " indicate a problem with your CMakeLists.txt file. ";
     cmSystemTools::Message(msg.c_str() ,"Warning");
     }