--- a/dist-files.mk	Fri Nov 26 16:31:38 2021 +0100
+++ b/dist-files.mk	Fri Nov 26 17:03:51 2021 +0100
@@ -535,6 +535,7 @@
   of-quaternion.mk \
   of-queueing.mk \
   of-signal-1-deprecated-warnings.patch \
+  of-signal-2-error_state.patch \
   of-signal.mk \
   of-sockets.mk \
   of-sparsersb-1-no-internal-mex-fcns.patch \

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/of-signal-2-error_state.patch	Fri Nov 26 17:03:51 2021 +0100
@@ -0,0 +1,141 @@
+# HG changeset patch
+# User Markus Mützel <markus.muetzel@gmx.de>
+# Date 1637941971 -3600
+#      Fri Nov 26 16:52:51 2021 +0100
+# Node ID 8d0372aeaf46d24f1d1b22ffc1bbfa32e7623250
+# Parent  7f535130c1912a5cc5021b5a761be02509219738
+Fix compilation with Octave 8 (bug #61564).
+
+* src/cl2bp.cc (Fcl2bp), src/sosfilt.cc (Fsosfilt), src/upfirdn.cc (Fupfirdn):
+Remove usage of `error_state`. It was unconditionally set to 0 since about 6
+years ago and will finally be removed in Octave 8.
+
+diff -r 7f535130c191 -r 8d0372aeaf46 src/cl2bp.cc
+--- a/src/cl2bp.cc	Thu Jun 17 00:46:56 2021 +0200
++++ b/src/cl2bp.cc	Fri Nov 26 16:52:51 2021 +0100
+@@ -89,30 +89,10 @@
+   }
+ 
+   const int m = args(0).int_value(true);
+-  if (error_state) {
+-    err_wrong_type_arg ("cl2bp", args(0));
+-    return retval;
+-  }
+   const double w1 = args(1).double_value();
+-  if (error_state) {
+-    err_wrong_type_arg ("cl2bp", args(1));
+-    return retval;
+-  }
+   const double w2 = args(2).double_value();
+-  if (error_state) {
+-    err_wrong_type_arg ("cl2bp", args(2));
+-    return retval;
+-  }
+   const ColumnVector up_vector(args(3).vector_value());
+-  if (error_state) {
+-    err_wrong_type_arg ("cl2bp", args(3));
+-    return retval;
+-  }
+   const ColumnVector lo_vector(args(4).vector_value());
+-  if (error_state) {
+-    err_wrong_type_arg ("cl2bp", args(4));
+-    return retval;
+-  }
+   if (up_vector.numel() != 3 || lo_vector.numel() != 3) {
+     error("cl2bp: The up and lo vectors must contain 3 values");
+     return retval;
+@@ -126,10 +106,6 @@
+   }
+ 
+   const int L = args(5).int_value(true);
+-  if (error_state) {
+-    err_wrong_type_arg ("cl2bp", args(5));
+-    return retval;
+-  }
+   if (L > 1000000) {
+     error("cl2bp: The \"gridsize\" parameter cannot exceed 1000000");
+     return retval;
+diff -r 7f535130c191 -r 8d0372aeaf46 src/sosfilt.cc
+--- a/src/sosfilt.cc	Thu Jun 17 00:46:56 2021 +0200
++++ b/src/sosfilt.cc	Fri Nov 26 16:52:51 2021 +0100
+@@ -55,12 +55,6 @@
+ 
+   Matrix sos( args(0).matrix_value() );
+ 
+-  if (error_state)
+-    {
+-      err_wrong_type_arg ("sosfilt", args(0));
+-      return retval;
+-    }
+-
+   if (sos.columns() != 6)
+     {
+       error("Second-order section matrix must be a non-empty Lx6 matrix");
+@@ -69,12 +63,6 @@
+ 
+   Matrix x( args(1).matrix_value() );
+ 
+-  if (error_state)
+-    {
+-      err_wrong_type_arg ("sosfilt", args(1));
+-      return retval;
+-    }
+-
+   int n=x.rows();
+   int m=x.columns();
+ 
+diff -r 7f535130c191 -r 8d0372aeaf46 src/upfirdn.cc
+--- a/src/upfirdn.cc	Thu Jun 17 00:46:56 2021 +0200
++++ b/src/upfirdn.cc	Fri Nov 26 16:52:51 2021 +0100
+@@ -107,51 +107,19 @@
+     }
+ 
+   ColumnVector h (args (1).vector_value ());
+-
+-  if (error_state)
+-    {
+-      err_wrong_type_arg ("upfirdn", args(1));
+-      return retval;
+-    }
+-
+   octave_idx_type p = args (2).idx_type_value ();
+-
+-  if (error_state)
+-    {
+-      err_wrong_type_arg ("upfirdn", args(2));
+-      return retval;
+-    }
+-
+   octave_idx_type q = args (3).idx_type_value ();
+ 
+-  if (error_state)
+-    {
+-      err_wrong_type_arg ("upfirdn", args(3));
+-      return retval;
+-    }
+-
+   // Do the dispatching
+   if (octave::signal::isreal (args (0)))
+     {
+       Matrix x = args (0).matrix_value ();
+-      if (error_state)
+-        {
+-          err_wrong_type_arg ("upfirdn", args(0));
+-          return retval;
+-        }
+-
+       Matrix y = upfirdn (x, h, p, q);
+       retval (0) = y;
+     }
+   else if (octave::signal::iscomplex (args (0)))
+     {
+       ComplexMatrix x = args (0).complex_matrix_value ();
+-      if (error_state)
+-        {
+-          err_wrong_type_arg ("upfirdn", args(0));
+-          return retval;
+-        }
+-
+       ComplexMatrix y = upfirdn (x, h, p, q);
+       retval (0) = y;
+     }