gnu: Add pkgconf-as-pkg-config.

* gnu/packages/pkg-config.scm (pkgconf-as-pkg-config): New variable.

Change-Id: If9ff93dbebde0c0d955cbe87af72e963913a6f45

gnu/packages/pkg-config.scm

@@ -205,3 +205,28 @@ provides access to most of pkgconf's functionality, to allow other tooling
 such as compilers and IDEs to discover and use libraries configured by
 pkgconf.")
     (license isc)))
+
+(define-public pkgconf-as-pkg-config
+  (package/inherit pkgconf
+    (name "pkgconf-as-pkg-config")
+    (build-system gnu-build-system)
+    (arguments
+     (list
+      #:tests? #f
+      #:phases
+      #~(modify-phases %standard-phases
+          (delete 'configure)
+          (delete 'build)
+          (replace 'install
+            (lambda* (#:key inputs #:allow-other-keys)
+              (let ((pkgconf (search-input-file inputs "bin/pkgconf")))
+                (mkdir-p (string-append #$output "/bin"))
+                (symlink pkgconf (string-append #$output "/bin/pkg-config"))
+                ;; Also make 'pkg.m4' available, some packages might expect it.
+                (mkdir-p (string-append #$output "/share"))
+                (symlink (string-append (dirname (dirname pkgconf))
+                                        "/share/aclocal")
+                         (string-append #$output "/share/aclocal"))))))))
+    (native-inputs '())
+    (inputs (list pkgconf))
+    (propagated-inputs '())))