--- a/libinterp/corefcn/mex.cc	Sat Dec 04 16:46:48 2021 +0100
+++ b/libinterp/corefcn/mex.cc	Sat Dec 04 11:00:16 2021 -0500
@@ -255,10 +255,43 @@
 
 // #define DEBUG 1
 
+#if DEBUG
+#  include <iostream>
+#endif
+
+static void *
+xmalloc (size_t n)
+{
+  void *ptr = std::malloc (n);
+
+#if DEBUG
+  std::cerr << "xmalloc (" << n << ") = " << ptr << std::endl;
+#endif
+
+  return ptr;
+}
+
+static void *
+xrealloc (void *ptr, size_t n)
+{
+  void *newptr = std::realloc (ptr, n);
+
+#if DEBUG
+  std::cerr << "xrealloc (" << ptr << ", " << n << ") = " << newptr
+            << std::endl;
+#endif
+
+  return newptr;
+}
+
 static void
 xfree (void *ptr)
 {
-  ::free (ptr);
+#if DEBUG
+  std::cerr << "xfree (" << ptr << ")" << std::endl;
+#endif
+
+  std::free (ptr);
 }
 
 static mwSize
@@ -3276,7 +3309,7 @@
   // Allocate memory.
   void * malloc_unmarked (std::size_t n)
   {
-    void *ptr = std::malloc (n);
+    void *ptr = xmalloc (n);
 
     if (! ptr)
       {
@@ -3332,7 +3365,7 @@
         auto p_local = m_memlist.find (ptr);
         auto p_global = s_global_memlist.find (ptr);
 
-        v = std::realloc (ptr, n);
+        v = xrealloc (ptr, n);
 
         if (v)
           {
@@ -3542,7 +3575,7 @@
 void *
 mxArray::malloc (std::size_t n)
 {
-  return mex_context ? mex_context->malloc_unmarked (n) : std::malloc (n);
+  return mex_context ? mex_context->malloc_unmarked (n) : xmalloc (n);
 }
 
 void *
@@ -3662,14 +3695,14 @@
 void *
 mxMalloc (std::size_t n)
 {
-  return mex_context ? mex_context->malloc (n) : std::malloc (n);
+  return mex_context ? mex_context->malloc (n) : xmalloc (n);
 }
 
 void *
 mxRealloc (void *ptr, std::size_t size)
 {
-  return mex_context ? mex_context->realloc (ptr, size)
-                     : std::realloc (ptr, size);
+  return (mex_context
+          ? mex_context->realloc (ptr, size) : xrealloc (ptr, size));
 }
 
 void

--- a/libinterp/corefcn/oct-stream.h	Sat Dec 04 16:46:48 2021 +0100
+++ b/libinterp/corefcn/oct-stream.h	Sat Dec 04 11:00:16 2021 -0500
@@ -37,12 +37,12 @@
 
 // These only appear as reference arguments or return values.
 
-template <typename T> class Array;
 class Cell;
 class octave_value;
 class octave_value_list;
 class string_vector;
 
+#include "Array-fwd.h"
 #include "data-conv.h"
 #include "mach-info.h"
 

--- a/libinterp/corefcn/pr-output.h	Sat Dec 04 16:46:48 2021 +0100
+++ b/libinterp/corefcn/pr-output.h	Sat Dec 04 11:00:16 2021 -0500
@@ -30,12 +30,12 @@
 
 #include <iosfwd>
 
+#include "Array-fwd.h"
 #include "oct-cmplx.h"
 #include "oct-inttypes-fwd.h"
 
 #include "pr-flt-fmt.h"
 
-template <typename T> class Array;
 class ComplexMatrix;
 class FloatComplexMatrix;
 class ComplexDiagMatrix;

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/liboctave/array/Array-fwd.h	Sat Dec 04 11:00:16 2021 -0500
@@ -0,0 +1,33 @@
+////////////////////////////////////////////////////////////////////////
+//
+// Copyright (C) 2021 The Octave Project Developers
+//
+// See the file COPYRIGHT.md in the top-level directory of this
+// distribution or <https://octave.org/copyright/>.
+//
+// This file is part of Octave.
+//
+// Octave is free software: you can redistribute it and/or modify it
+// under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// Octave is distributed in the hope that it will be useful, but
+// WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with Octave; see the file COPYING.  If not, see
+// <https://www.gnu.org/licenses/>.
+//
+////////////////////////////////////////////////////////////////////////
+
+#if ! defined (octave_Array_fwd_h)
+#define octave_Array_fwd_h 1
+
+#include "octave-config.h"
+
+template <typename T> class OCTARRAY_API Array;
+
+#endif

--- a/liboctave/array/Array.h	Sat Dec 04 16:46:48 2021 +0100
+++ b/liboctave/array/Array.h	Sat Dec 04 11:00:16 2021 -0500
@@ -35,6 +35,7 @@
 #include <iosfwd>
 #include <string>
 
+#include "Array-fwd.h"
 #include "dim-vector.h"
 #include "idx-vector.h"
 #include "lo-error.h"
@@ -122,9 +123,6 @@
 //!   - string_vector: Array<std::string> with 1 column
 //!   - Cell: Array<octave_value>, equivalent to an Octave cell.
 
-// forward declare template with visibility attribute
-template <typename T> class OCTARRAY_API Array;
-
 template <typename T>
 class
 Array

--- a/liboctave/array/Range.h	Sat Dec 04 16:46:48 2021 +0100
+++ b/liboctave/array/Range.h	Sat Dec 04 11:00:16 2021 -0500
@@ -30,13 +30,12 @@
 
 #include <iosfwd>
 
+#include "Array-fwd.h"
 #include "dMatrix.h"
 #include "dim-vector.h"
 #include "lo-error.h"
 #include "oct-sort.h"
 
-template <typename T> class Array;
-
 namespace octave
 {
   template <typename T>

--- a/liboctave/array/Sparse.h	Sat Dec 04 16:46:48 2021 +0100
+++ b/liboctave/array/Sparse.h	Sat Dec 04 11:00:16 2021 -0500
@@ -35,8 +35,9 @@
 #include <iosfwd>
 #include <string>
 
+#include "Array-fwd.h"
+
 class PermMatrix;
-template <typename T> class Array;
 
 // Two dimensional sparse class.  Handles the reference counting for
 // all the derived classes.

--- a/liboctave/array/dim-vector.h	Sat Dec 04 16:46:48 2021 +0100
+++ b/liboctave/array/dim-vector.h	Sat Dec 04 11:00:16 2021 -0500
@@ -36,11 +36,10 @@
 #include <initializer_list>
 #include <string>
 
+#include "Array-fwd.h"
 #include "oct-atomic.h"
 #include "oct-refcount.h"
 
-template <typename T> class Array;
-
 //! Vector representing the dimensions (size) of an Array.
 //!
 //! A dim_vector is used to represent dimensions of an Array.  It is used

--- a/liboctave/array/idx-vector.h	Sat Dec 04 16:46:48 2021 +0100
+++ b/liboctave/array/idx-vector.h	Sat Dec 04 11:00:16 2021 -0500
@@ -35,11 +35,11 @@
 #include <iosfwd>
 #include <memory>
 
+#include "Array-fwd.h"
 #include "dim-vector.h"
 #include "oct-inttypes-fwd.h"
 #include "oct-refcount.h"
 
-template <typename T> class Array;
 template <typename T> class Sparse;
 
 namespace octave

--- a/liboctave/array/module.mk	Sat Dec 04 16:46:48 2021 +0100
+++ b/liboctave/array/module.mk	Sat Dec 04 11:00:16 2021 -0500
@@ -1,6 +1,7 @@
 ARRAY_INC = \
+  %reldir%/Array-fwd.h \
+  %reldir%/Array-util.h \
   %reldir%/Array.h \
-  %reldir%/Array-util.h \
   %reldir%/boolMatrix.h \
   %reldir%/boolNDArray.h \
   %reldir%/boolSparse.h \

--- a/liboctave/numeric/oct-spparms.h	Sat Dec 04 16:46:48 2021 +0100
+++ b/liboctave/numeric/oct-spparms.h	Sat Dec 04 11:00:16 2021 -0500
@@ -31,11 +31,10 @@
 #include <iosfwd>
 #include <string>
 
+#include "Array-fwd.h"
 #include "str-vec.h"
 #include "dColVector.h"
 
-template <typename T> class Array;
-
 #define OCTAVE_SPARSE_CONTROLS_SIZE 13
 
 namespace octave

--- a/liboctave/numeric/qr.h	Sat Dec 04 16:46:48 2021 +0100
+++ b/liboctave/numeric/qr.h	Sat Dec 04 11:00:16 2021 -0500
@@ -28,7 +28,7 @@
 
 #include "octave-config.h"
 
-template <typename T> class Array;
+#include "Array-fwd.h"
 
 namespace octave
 {

--- a/liboctave/util/oct-base64.h	Sat Dec 04 16:46:48 2021 +0100
+++ b/liboctave/util/oct-base64.h	Sat Dec 04 11:00:16 2021 -0500
@@ -30,10 +30,9 @@
 
 #include <string>
 
+#include "Array-fwd.h"
 #include "intNDArray.h"
 
-template <typename T> class Array;
-
 namespace octave
 {
   extern OCTAVE_API bool

--- a/liboctave/util/url-transfer.h	Sat Dec 04 16:46:48 2021 +0100
+++ b/liboctave/util/url-transfer.h	Sat Dec 04 11:00:16 2021 -0500
@@ -33,10 +33,9 @@
 #include <ostream>
 #include <string>
 
+#include "Array-fwd.h"
 #include "str-vec.h"
 
-template <typename T> class Array;
-
 namespace octave
 {
   struct weboptions