STYLE: Factor CollectOriginalDirectories code

This factors code out of cmOrderDirectories::CollectOriginalDirectories
into cmOrderDirectories::AddOriginalDirectories.  Later a new call will
be added, and this is more readable anyway.

Source/cmOrderDirectories.cxx

@@ -393,26 +393,7 @@ void cmOrderDirectories::CollectOriginalDirectories()
   // Add user directories specified for inclusion.  These should be
   // indexed first so their original order is preserved as much as
   // possible subject to the constraints.
-  for(std::vector<std::string>::const_iterator
-        di = this->UserDirectories.begin();
-      di != this->UserDirectories.end(); ++di)
-    {
-    // We never explicitly specify implicit link directories.
-    if(this->ImplicitDirectories.find(*di) !=
-       this->ImplicitDirectories.end())
-      {
-      continue;
-      }
-
-    // Skip the empty string.
-    if(di->empty())
-      {
-      continue;
-      }
-
-    // Add this directory.
-    this->AddOriginalDirectory(*di);
-    }
+  this->AddOriginalDirectories(this->UserDirectories);
 
   // Add directories containing constraints.
   for(unsigned int i=0; i < this->ConstraintEntries.size(); ++i)
@@ -438,6 +419,32 @@ int cmOrderDirectories::AddOriginalDirectory(std::string const& dir)
   return i->second;
 }
 
+//----------------------------------------------------------------------------
+void
+cmOrderDirectories
+::AddOriginalDirectories(std::vector<std::string> const& dirs)
+{
+  for(std::vector<std::string>::const_iterator di = dirs.begin();
+      di != dirs.end(); ++di)
+    {
+    // We never explicitly specify implicit link directories.
+    if(this->ImplicitDirectories.find(*di) !=
+       this->ImplicitDirectories.end())
+      {
+      continue;
+      }
+
+    // Skip the empty string.
+    if(di->empty())
+      {
+      continue;
+      }
+
+    // Add this directory.
+    this->AddOriginalDirectory(*di);
+    }
+}
+
 //----------------------------------------------------------------------------
 struct cmOrderDirectoriesCompare
 {

Source/cmOrderDirectories.h

@@ -66,6 +66,7 @@ private:
   std::vector<int> DirectoryVisited;
   void CollectOriginalDirectories();
   int AddOriginalDirectory(std::string const& dir);
+  void AddOriginalDirectories(std::vector<std::string> const& dirs);
   void FindConflicts();
   void FindImplicitConflicts();
   void OrderDirectories();