Fix for which command deprecation in debian Bookworm/unstable.

(cherry picked from commit f96ed7ad)

src/utilities/x13/select_x13_binary.m

@@ -47,7 +47,7 @@ elseif isunix()
         x13_binary = sprintf('%s%s%s%s', x13_binary, '32', filesep(), 'x13as');
     end
     if ~exist(x13_binary, 'file')
-        [status, x13_binary] = system('which x13as');
+        [status, x13_binary] = system('command -v x13as');
         if ~status
             x13_binary = deblank(x13_binary);
         end