Use matrix concatenation for strings, rather than cstrcat(), for clarity and performance. matrix concatenation is ~80% faster than cstrcat(). * doc/interpreter/strings.txi: Document preference for matrix concatenation as opposed to alternatives. * doc/interpreter/geometryimages.m, doc/interpreter/interpimages.m, doc/interpreter/plotimages.m, doc/interpreter/sparseimages.m, doc/interpreter/splineimages.m, scripts/general/genvarname.m, scripts/general/int2str.m, scripts/general/num2str.m, scripts/help/__makeinfo__.m, scripts/help/help.m, scripts/miscellaneous/copyfile.m, scripts/miscellaneous/dir.m, scripts/miscellaneous/edit.m, scripts/miscellaneous/fact.m, scripts/miscellaneous/fullfile.m, scripts/miscellaneous/mkoctfile.m, scripts/miscellaneous/movefile.m, scripts/miscellaneous/perl.m, scripts/miscellaneous/python.m, scripts/miscellaneous/run.m, scripts/miscellaneous/tempdir.m, scripts/miscellaneous/unpack.m, scripts/pkg/private/configure_make.m, scripts/pkg/private/create_pkgadddel.m, scripts/pkg/private/extract_pkg.m, scripts/pkg/private/get_description.m, scripts/pkg/private/get_forge_pkg.m, scripts/pkg/private/getarch.m, scripts/pkg/private/getarchprefix.m, scripts/pkg/private/install.m, scripts/pkg/private/installed_packages.m, scripts/pkg/private/load_packages_and_dependencies.m, scripts/pkg/private/rebuild.m, scripts/pkg/private/repackage.m, scripts/pkg/private/shell.m, scripts/pkg/private/uninstall.m, scripts/plot/private/__go_draw_axes__.m, scripts/signal/spectral_adf.m, scripts/signal/spectral_xdf.m, scripts/statistics/tests/z_test.m, scripts/statistics/tests/z_test_2.m, scripts/strings/mat2str.m, scripts/strings/strtok.m, scripts/testfun/__run_test_suite__.m, scripts/testfun/assert.m, scripts/testfun/demo.m, scripts/testfun/speed.m, scripts/testfun/test.m, test/eval-catch.tst, test/io.tst, test/try.tst: Replace cstrcat() with matrix concatenation where possible.

--- a/scripts/testfun/assert.m
+++ b/scripts/testfun/assert.m
@@ -61,9 +61,9 @@
 
   in = deblank (argn(1,:));
   for i = 2:rows (argn)
-    in = cstrcat (in, ",", deblank (argn(i,:)));
+    in = [in "," deblank(argn(i,:))];
   endfor
-  in = cstrcat ("(", in, ")");
+  in = ["(" in ")"];
 
   if (nargin == 1 || (nargin > 1 && islogical (cond) && ischar (varargin{1})))
     if ((! isnumeric (cond) && ! islogical (cond)) || ! all (cond(:)))
@@ -147,7 +147,7 @@
         ## Without explicit tolerance, be more strict.
         if (! strcmp (class (cond), class (expected)))
           iserror = 1;
-          coda = cstrcat ("Class ", class (cond), " != ", class (expected));
+          coda = ["Class " class (cond) " != " class(expected)];
         elseif (isnumeric (cond))
           if (issparse (cond) != issparse (expected))
             if (issparse (cond))
@@ -228,9 +228,9 @@
     if (! isempty (idx))
       str2 = str2 (idx(1):idx(end));
     endif
-    msg = cstrcat ("assert ", in, " expected\n", str, "\nbut got\n", str2);
+    msg = ["assert " in " expected\n" str "\nbut got\n" str2];
     if (! isempty (coda))
-      msg = cstrcat (msg, "\n", coda);
+      msg = [msg, "\n", coda];
     endif
     error ("%s", msg);
   endif