Please describe the problem:
On compiling, gda-value.h gives a warning. It prevents compiling software with -Werror that uses GdaValue.

Steps to reproduce:
1. Create a piece of software that uses GdaValue (including gda-value.h).
2. Compile this software with -Werror



Actual results:
An error like this:
In file included from /usr/include/libgda-1.2/libgda/gda-field.h:27,
                 from /usr/include/libgda-1.2/libgda/gda-row.h:27,
                 from /usr/include/libgda-1.2/libgda/gda-data-model.h:30,
                 from /usr/include/libgda-1.2/libgda/gda-connection.h:28,
                 from /usr/include/libgda-1.2/libgda/gda-client.h:27,
                 from /usr/include/libgda-1.2/libgda/libgda.h:28,
                 from /usr/include/libfisterra-server/f_egb_util.h:27,
                 from f_dao_replication_module.h:31,
                 from f_dao_replication_module.c:25:
/usr/include/libgda-1.2/libgda/gda-value.h:183: warning: type qualifiers ignored on function return type


Expected results:
No warning

Does this happen every time?
Yes, if you use gcc 4.x

Other information:
The problem is with the use of const in a non-pointer type:
G_CONST_RETURN gpointer gda_value_get_binary (GdaValue *value, glong *size);

It's not allowed. The macro should be removed in this function declaration.