whois: init at 5.2.10 and share with mkpasswd

Close #7979.
This commit adds a much more usable whois tool compared to the ones in
busybox and inetutils.

The sources for whois and mkpasswd from Debian are both located in the whois
git repository for historical reasons.

pkgs/tools/security/mkpasswd/default.nix

@@ -1,30 +1,21 @@
-{ stdenv, fetchFromGitHub }:
+{ stdenv, whois, perl }:
 
-stdenv.mkDerivation rec {
-  name = "mkpasswd-${version}";
+stdenv.mkDerivation {
+  name = "mkpasswd-${whois.version}";
 
-  version = "5.1.1";
+  src = whois.src;
 
-  src = fetchFromGitHub {
-    owner = "rfc1036";
-    repo = "whois";
-    rev = "v${version}";
-    sha256 = "026x8byx8pcpkdxca64368p0nlspk4phw18jg4p04di6cg6nc1m5";
-  };
-
-  preConfigure = ''
-    substituteInPlace Makefile --replace "prefix = /usr" "prefix = $out"
-  '';
+  buildInputs = [ perl ];
 
+  preConfigure = whois.preConfigure;
   buildPhase = "make mkpasswd";
-
   installPhase = "make install-mkpasswd";
 
   meta = with stdenv.lib; {
     homepage = http://packages.qa.debian.org/w/whois.html;
     description = "Overfeatured front-end to crypt, from the Debian whois package";
     license = licenses.gpl2;
-    maintainers = [ maintainers.cstrahan ];
+    maintainers = with maintainers; [ cstrahan fpletz ];
     platforms = platforms.linux;
   };
 }