prepare showing hint for middleare.

lisp/install-sbcl.lisp

@@ -71,7 +71,10 @@
          (when default
            (set-opt name (eql default t)))
          (with name)))
-  (cons t argv))
+  (cons (if (opt "core-compression")
+            (require-system-package "zlib")
+            t)
+        argv))
 
 (defun sbcl-start (argv)
   (when (and (find (getf argv :target) '("sbcl-bin" "sbcl") :test 'equal)

lisp/util-install.lisp

@@ -124,4 +124,9 @@
                      (uiop:run-program `(,(sh) "-lc" ,(format nil "cd ~S;pwd" (uiop:native-namestring path)))
                                        :output :string)))
 
+(defun require-system-package (&rest packages)
+  "check installation of system library like 'zlib' and show how to install."
+  (declare (ignorable packages))
+  t)
+
 (pushnew :ros.install.util *features*)