Tracker: re-add includes that were lost during merge

src/kits/tracker/FindPanel.cpp

@@ -42,6 +42,7 @@ All rights reserved.
 #include <parsedate.h>
 #include <stdlib.h>
 #include <string.h>
+#include <strings.h>
 
 #include <Application.h>
 #include <Box.h>

src/kits/tracker/NavMenu.cpp

@@ -40,8 +40,9 @@ their respective holders. All rights reserved.
 
 #include <algorithm>
 
-#include <string.h>
 #include <stdlib.h>
+#include <string.h>
+#include <strings.h>
 
 #include <Application.h>
 #include <Catalog.h>