build-system/asdf: Add option to compress programs.

* guix/build/lisp-utils.scm (build-program): Add `compress?' key argument.
(generate-executable-for-system): Same.
(generate-executable): Same.

guix/build/lisp-utils.scm

@@ -220,12 +220,19 @@ Also load TEST-ASD-FILE if necessary."
   "Return a lisp keyword for the concatenation of STRINGS."
   (string->symbol (apply string-append ":" strings)))
 
-(define (generate-executable-for-system type system)
+(define* (generate-executable-for-system type system #:key compress?)
   "Use LISP to generate an executable, whose TYPE can be 'asdf:image-op or
 'asdf:program-op.  The latter will always be standalone.  Depends on having
 created a \"SYSTEM-exec\" system which contains the entry program."
   (lisp-eval-program
    `((require :asdf)
+     ;; Only SBCL supports compression as of 2019-09-02.
+     ,(if (and compress? (string=? (%lisp-type) "sbcl"))
+          '(defmethod asdf:perform ((o asdf:image-op) (c asdf:system))
+                      (uiop:dump-image (asdf:output-file o c)
+                                       :executable t
+                                       :compression t))
+          '())
      (asdf:operate ',type ,(string-append system "-exec")))))
 
 (define (generate-executable-wrapper-system system dependencies)
@@ -339,6 +346,7 @@ which are not nested."
                         (dependency-prefixes (list (library-output outputs)))
                         (dependencies (list (basename program)))
                         entry-program
+                        compress?
                         #:allow-other-keys)
   "Generate an executable program containing all DEPENDENCIES, and which will
 execute ENTRY-PROGRAM.  The result is placed in PROGRAM.  When executed, it
@@ -350,6 +358,7 @@ retained."
                        #:dependencies dependencies
                        #:dependency-prefixes dependency-prefixes
                        #:entry-program entry-program
+                       #:compress? compress?
                        #:type 'asdf:program-op)
   (let* ((name (basename program))
          (bin-directory (dirname program)))
@@ -382,6 +391,7 @@ DEPENDENCY-PREFIXES to ensure references to those libraries are retained."
                               dependency-prefixes
                               entry-program
                               type
+                              compress?
                               #:allow-other-keys)
   "Generate an executable by using asdf operation TYPE, containing whithin the
 image all DEPENDENCIES, and running ENTRY-PROGRAM in the case of an
@@ -405,7 +415,7 @@ references to those libraries are retained."
                `(((,bin-directory :**/ :*.*.*)
                   (,bin-directory :**/ :*.*.*)))))))
 
-    (generate-executable-for-system type name)
+    (generate-executable-for-system type name #:compress? compress?)
 
     (let* ((after-store-prefix-index
             (string-index out-file #\/