Fix typing problems with GR_KB_* constants

pcbnew/block_module_editor.cpp

@@ -78,7 +78,7 @@ static void MoveMarkedItems( MODULE* module, wxPoint offset );
 static void DeleteMarkedItems( MODULE* module );
 
 
-int FOOTPRINT_EDIT_FRAME::BlockCommand( int key )
+int FOOTPRINT_EDIT_FRAME::BlockCommand( EDA_KEY key )
 {
     int cmd;
 
@@ -88,7 +88,14 @@ int FOOTPRINT_EDIT_FRAME::BlockCommand( int key )
         cmd = key & 0xFF;
         break;
 
-    case - 1:
+    case EDA_KEY_C( 0xffffffff ):   // -1
+        // Historically, -1 has been used as a key, which can cause bit flag
+        // clashes with unaware code. On debug builds, catch any old code that
+        // might still be doing this. TODO: remove if sure all this old code is gone.
+        wxFAIL_MSG( "negative EDA_KEY value should be converted to GR_KEY_INVALID" );
+        // fall through on release builds
+
+    case GR_KEY_INVALID:
         cmd = BLOCK_PRESELECT_MOVE;
         break;