import: print: Honor the outputs of inputs (!).

Fixes <http://bugs.gnu.org/35893>.
Reported by Jesse Gibbons <jgibbons2357@gmail.com>.

* guix/import/print.scm (package->code)[package-lists->code]: Preserve
OUT in the result.
* tests/print.scm (define-with-source): New macro.
(pkg): Use it.
(pkg-source): New variable.
(pkg-with-inputs, pkg-with-inputs-source): New variables.
("simple package"): Refer to 'pkg-source'.
("package with inputs"): New test.

guix/import/print.scm

@@ -94,12 +94,13 @@ when evaluated."
           (map (match-lambda
                  ((label pkg . out)
                   (let ((mod (package-module-name pkg)))
-                    (list label
+                    (cons* label
                            ;; FIXME: using '@ certainly isn't pretty, but it
                            ;; avoids having to import the individual package
                            ;; modules.
                            (list 'unquote
-                                (list '@ mod (variable-name pkg mod)))))))
+                                 (list '@ mod (variable-name pkg mod)))
+                           out))))
                lsts)))
 
   (let ((name                (package-name package))

tests/print.scm

@@ -24,9 +24,14 @@
   #:use-module (guix licenses)
   #:use-module (srfi srfi-64))
 
+(define-syntax-rule (define-with-source object source expr)
+  (begin
+    (define object expr)
+    (define source 'expr)))
+
 (test-begin "print")
 
-(define pkg
+(define-with-source pkg pkg-source
   (package
     (name "test")
     (version "1.2.3")
@@ -43,9 +48,8 @@
     (description "This is a dummy package.")
     (license gpl3+)))
 
-(test-equal "simple package"
-  (package->code pkg)
-  '(package
+(define-with-source pkg-with-inputs pkg-with-inputs-source
+  (package
     (name "test")
     (version "1.2.3")
     (source (origin
@@ -56,9 +60,19 @@
                (base32
                 "070pwb7brdcn1mfvplkd56vjc7lbz4iznzkqvfsakvgbv68k71ah"))))
     (build-system gnu-build-system)
+    (inputs `(("coreutils" ,(@ (gnu packages base) coreutils))
+              ("glibc" ,(@ (gnu packages base) glibc) "debug")))
     (home-page "http://gnu.org")
     (synopsis "Dummy")
     (description "This is a dummy package.")
     (license gpl3+)))
 
+(test-equal "simple package"
+  pkg-source
+  (package->code pkg))
+
+(test-equal "package with inputs"
+  pkg-with-inputs-source
+  (package->code pkg-with-inputs))
+
 (test-end "print")