gnu: guix: Remove unnecessary dependencies.

This reverts 0fda048652, instead moving
the dependencies needed for ‘make dist’ to ‘manifest.scm’.

Removing this extra dependencies make it simpler to build the ‘guix’
package in particular on less-capable systems like i586-gnu.

* gnu/packages/package-management.scm (guix)[native-inputs]: Remove
IMAGEMAGICK and PERL.  Use GRAPHVIZ-MINIMAL instead of GRAPHVIZ.
* manifest.scm: Use the full-blown ‘graphviz’ package; add ‘imagemagick’
and ‘perl’.

Reported-by: Janneke Nieuwenhuizen <janneke@gnu.org>
Change-Id: Ia9d05c699e3cc2f9a9235a67f8ec840c26b66a82

gnu/packages/package-management.scm

@@ -493,10 +493,8 @@ $(prefix)/etc/openrc\n")))
                        ("automake" ,automake)
                        ("gettext" ,gettext-minimal)
                        ("texinfo" ,texinfo)
-                       ("graphviz" ,graphviz) ;non-minimal for PDF support
+                       ("graphviz" ,graphviz-minimal)
                        ("font-ghostscript" ,font-ghostscript) ;fonts for 'dot'
-                       ("imagemagick" ,imagemagick) ;for 'make dist'
-                       ("perl" ,perl)               ;for 'make dist'
                        ("help2man" ,help2man)
                        ("po4a" ,po4a-minimal)))
       (inputs

manifest.scm

@@ -24,11 +24,25 @@
 ;;
 ;;     guix shell --pure -m manifest.scm hello ...
 
+(use-modules (guix packages))
+
 (concatenate-manifests
- (list (package->development-manifest (specification->package "guix"))
+ (list (package->development-manifest
+        (let ((guix (specification->package "guix")))
+          (package/inherit guix
+            ;; Replace with non-minimal Graphviz for PDF support.
+            (native-inputs (modify-inputs (package-native-inputs guix)
+                             (replace "graphviz"
+                               (specification->package "graphviz")))))))
+
        ;; Extra packages used by unit tests.
        (specifications->manifest (list "gnupg"))
 
+       ;; Packages needed for 'make dist' and 'make distcheck'.
+       (specifications->manifest
+        (list "imagemagick"
+              "perl"))
+
        ;; Useful extras for patches submission.
        (specifications->manifest
         (list "b4"