Add build rule for build-octave (bug #49503). * src/build-octave.mk: Add new build rule for build-octave which can be used for cross-building binary packages that depend on Octave as a build tool. * dist-files.mk: Add new file to list. * index.html: Add new package to list. * src/of-communications.mk, src/of-image.mk, src/of-mapping.mk, src/of-optiminterp.mk, src/of-sparsersb.mk, src/of-statistics.mk, src/of-windows.mk: Add optional dependency on build-octave. * configure.ac: Add new configure switch "--disable-system-octave" that is needed to build the build-octave package. * Makefile.in: Add variable "USE_SYSTEM_OCTAVE". Exclude build-octave from the default build tools and build it only if a package explicitly depends on it. Display warning about missing native Octave version only if necessary.

--- a/src/Mshichmanhodgesmosfet.cc	2015-08-17 19:02:20.000000000 +0200
+++ a/src/Mshichmanhodgesmosfet.cc	2018-12-24 15:28:45.472849403 +0100
@@ -319,7 +319,7 @@
   if (args(1).length() == args(2).length())
     {
       parameters     = args(1).column_vector_value();
-      parameternames = args(2).all_strings();
+      parameternames = args(2).string_vector_value();
     }
   else
     error("Mshichmanhodgesmosfet: parameters and parameternames are expected to have the same length.\n");
@@ -329,7 +329,7 @@
   else
     error("Mshichmanhodgesmosfet: five external values expected.\n");
   // Internal variables
-  if (args(4).is_empty())
+  if (args(4).isempty())
     {}
   else if (args(4).length() == 5)
     intvar = args(4).column_vector_value();