profiles: Honor search paths of propagated inputs.

Fixes <http://bugs.gnu.org/22073>.
Reported by Federico Beffa <beffa@ieee.org>.

* guix/profiles.scm (package->manifest-entry): Use
'package-transitive-native-search-paths' when computing
'search-paths' field.
* tests/profiles.scm ("package->manifest-entry, search paths"): New test.

guix/profiles.scm

@@ -176,7 +176,7 @@ omitted or #f, use the first output of PACKAGE."
      (output (or output (car (package-outputs package))))
      (item package)
      (dependencies (delete-duplicates deps))
-     (search-paths (package-native-search-paths package)))))
+     (search-paths (package-transitive-native-search-paths package)))))
 
 (define (packages->manifest packages)
   "Return a list of manifest entries, one for each item listed in PACKAGES.

tests/profiles.scm

@@ -32,6 +32,7 @@
   #:use-module (ice-9 regex)
   #:use-module (ice-9 popen)
   #:use-module (rnrs io ports)
+  #:use-module (srfi srfi-1)
   #:use-module (srfi srfi-11)
   #:use-module (srfi srfi-64))
 
@@ -224,6 +225,14 @@
                            (package-native-search-paths
                             packages:guile-2.0)))))))))
 
+(test-assert "package->manifest-entry, search paths"
+  ;; See <http://bugs.gnu.org/22073>.
+  (let ((mpl (@ (gnu packages python) python2-matplotlib)))
+    (lset= eq?
+           (package-transitive-native-search-paths mpl)
+           (manifest-entry-search-paths
+            (package->manifest-entry mpl)))))
+
 (test-assertm "etc/profile"
   ;; Make sure we get an 'etc/profile' file that at least defines $PATH.
   (mlet* %store-monad