Fix using WX_DECLARE_OBJARRAY() with pointer types

While this doesn't make, and never made, any sense (pointers should be
stored in a plain, non-object array), we still should continue to
support it for compatibility.

Fix the problem introduced by 97684a9267
by writing "T const&" instead of "const T&" as the latter didn't have
the same meaning when the macro parameter "T" expanded into "U*" as
"const" applied to "U", making this type incompatible with the actual
one.

Also extend the unit test to check for this.

include/wx/dynarray.h

@@ -652,7 +652,7 @@ private:
     classdecl wxObjectArrayTraitsFor##name                                    \
     {                                                                         \
     public:                                                                   \
-        static T* Clone(const T& item);                                       \
+        static T* Clone(T const& item);                                       \
         static void Free(T* p);                                               \
     };                                                                        \
     typedef wxBaseObjectArray<T, wxObjectArrayTraitsFor##name>                \

tests/arrays/arrays.cpp

@@ -95,6 +95,17 @@ WX_DECLARE_OBJARRAY(Bar, ArrayBars);
 #include "wx/arrimpl.cpp"
 WX_DEFINE_OBJARRAY(ArrayBars)
 
+// ----------------------------------------------------------------------------
+// another object array test
+// ----------------------------------------------------------------------------
+
+// This code doesn't make any sense, as object arrays should be used with
+// objects, not pointers, but it used to work, so check that it continues to
+// compile.
+WX_DECLARE_OBJARRAY(Bar*, ArrayBarPtrs);
+#include "wx/arrimpl.cpp"
+WX_DEFINE_OBJARRAY(ArrayBarPtrs)
+
 // ----------------------------------------------------------------------------
 // helpers for sorting arrays and comparing items
 // ----------------------------------------------------------------------------
@@ -165,6 +176,7 @@ private:
         CPPUNIT_TEST( wxStringArraySplitJoinTest );
 
         CPPUNIT_TEST( wxObjArrayTest );
+        CPPUNIT_TEST( wxObjArrayPtrTest );
         CPPUNIT_TEST( wxArrayUShortTest );
         CPPUNIT_TEST( wxArrayIntTest );
         CPPUNIT_TEST( wxArrayCharTest );
@@ -181,6 +193,7 @@ private:
     void wxStringArrayJoinTest();
     void wxStringArraySplitJoinTest();
     void wxObjArrayTest();
+    void wxObjArrayPtrTest();
     void wxArrayUShortTest();
     void wxArrayIntTest();
     void wxArrayCharTest();
@@ -567,6 +580,13 @@ void ArraysTestCase::wxObjArrayTest()
     CPPUNIT_ASSERT_EQUAL( 0, Bar::GetNumber() );
 }
 
+void ArraysTestCase::wxObjArrayPtrTest()
+{
+    // Just check that instantiating this class compiles.
+    ArrayBarPtrs barptrs;
+    CPPUNIT_ASSERT_EQUAL( 0, barptrs.size() );
+}
+
 #define TestArrayOf(name)                                                     \
                                                                               \
 void ArraysTestCase::wxArray ## name ## Test()                                \