--- src/project.h.orig
+++ src/project.h
@@ -122,6 +122,14 @@
 	graphical user interface.
 */
 
+class project;
+
+bool ReadGPR_OLD(project &, istream &, bool, bool = false);		///< this is for the very old version.
+bool ReadGPR_v100(project &, istream &, bool, bool = false);		///< this is for the version 1.00.
+bool ReadGPR_v110(project &, istream &, bool, bool = false);		///< this is for the version 1.10.
+/// This is an input function for the v1.11 ghemical file format.
+bool ReadGPR(project &, istream &, bool, bool = false);
+
 class project :
 	public custom_transformer_client,
 	public model
@@ -207,11 +215,11 @@
 
 // methods for file I/O : ReadGPR and WriteGPR are friend functions so that it would be easier to "borrow" them elsewhere...
 // ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-	friend bool ReadGPR_OLD(project &, istream &, bool, bool = false);		///< this is for the very old version.
-	friend bool ReadGPR_v100(project &, istream &, bool, bool = false);		///< this is for the version 1.00.
-	friend bool ReadGPR_v110(project &, istream &, bool, bool = false);		///< this is for the version 1.10.
+	friend bool ReadGPR_OLD(project &, istream &, bool, bool);		///< this is for the very old version.
+	friend bool ReadGPR_v100(project &, istream &, bool, bool);		///< this is for the version 1.00.
+	friend bool ReadGPR_v110(project &, istream &, bool, bool);		///< this is for the version 1.10.
 /// This is an input function for the v1.11 ghemical file format.
-	friend bool ReadGPR(project &, istream &, bool, bool = false);
+	friend bool ReadGPR(project &, istream &, bool, bool);
 	
 	friend void WriteGPR_v100(project &, ostream &);	///< this is for the version 1.00.
 /// This is an output function for the v1.11 ghemical file format.