gnu: guile-2.0: Add libxcrypt dependency.

* gnu/packages/guile.scm (guile-2.0): Add libxcrypt dependency, and include it
in the pkg-config file's flags.
* gnu/packages/commencement.scm (guile-final): Explicitely exclude libxcrypt dependency.

Change-Id: Ie01913971b225c4dd23dcfdb96348d4e11042da8

gnu/packages/commencement.scm

@@ -3297,8 +3297,18 @@ (define with-boot4
 (define-public guile-final
   ;; This package must be public because other modules refer to it.  However,
   ;; mark it as hidden so that 'fold-packages' ignores it.
-  (with-boot4 (hidden-package
-               (package-with-bootstrap-guile guile-3.0/pinned))))
+  (let ((parent (with-boot4 (hidden-package
+                             (package-with-bootstrap-guile guile-3.0/pinned)))))
+    (package
+      (inherit parent)
+      (inputs
+       (modify-inputs (package-inputs parent)
+         (delete "libxcrypt")))
+      (arguments
+       (substitute-keyword-arguments (package-arguments parent)
+         ((#:phases phases #~%standard-phases)
+          #~(modify-phases #$phases
+              (delete 'add-libxcrypt-reference-pkgconfig))))))))
 
 (define-public glibc-utf8-locales-final
   ;; Now that we have GUILE-FINAL, build the UTF-8 locales.  They are needed

gnu/packages/guile.scm

@@ -176,7 +176,7 @@ (define-public guile-2.0
                 (list this-package)
                 '())))
    (inputs
-    (append (list libffi)
+    (append (list libffi libxcrypt)
             (libiconv-if-needed)
 
             ;; We need Bash when cross-compiling because some of the scripts
@@ -251,7 +251,19 @@ (define-public guile-2.0
                          '(search-input-file inputs "/bin/bash"))
                         (else
                          '(string-append bash "/bin/bash")))))
-              #t))))))
+              #t)))
+        (add-after 'install 'add-libxcrypt-reference-pkgconfig
+          (lambda* (#:key inputs outputs #:allow-other-keys)
+            (define out (assoc-ref outputs "out"))
+            (define libxcrypt
+              (false-if-exception
+               (dirname (search-input-file inputs "lib/libcrypt.so.1"))))
+            (when libxcrypt
+              (substitute*
+                  (find-files (string-append out "/lib/pkgconfig")
+                              ".*\\.pc")
+                (("-lcrypt")
+                 (string-append "-L" libxcrypt " -lcrypt")))))))))
 
    (native-search-paths
     (list (search-path-specification