sagelib: fix missing pkgs.pkgconfig

Again: eb3f0aef43 #54306
Apparently the derivation needs both pkgconfigs
(it fails when missing either).

pkgs/applications/science/math/sage/default.nix

@@ -35,6 +35,7 @@ let
         inherit flint ecl arb;
         inherit sage-src pynac singular;
         linbox = pkgs.linbox.override { withSage = true; };
+        pkg-config = pkgs.pkgconfig; # not to confuse with pythonPackages.pkgconfig
       };
     };
   };

pkgs/applications/science/math/sage/sagelib.nix

@@ -30,6 +30,7 @@
 , numpy
 , pari
 , pkgconfig
+, pkg-config
 , planarity
 , ppl
 , pynac
@@ -63,6 +64,7 @@ buildPythonPackage rec {
     iml
     perl
     jupyter_core
+    pkg-config
   ];
 
   buildInputs = [