gmp: use pname and version

pkgs/development/libraries/gmp/4.3.2.nix

@@ -1,10 +1,11 @@
 { lib, stdenv, fetchurl, m4, cxx ? true }:
 
 let self = stdenv.mkDerivation rec {
-  name = "gmp-4.3.2";
+  pname = "gmp";
+  version = "4.3.2";
 
   src = fetchurl {
-    url = "mirror://gnu/gmp/${name}.tar.bz2";
+    url = "mirror://gnu/gmp/gmp-${version}.tar.bz2";
     sha256 = "0x8prpqi9amfcmi7r4zrza609ai9529pjaq0h4aw51i867064qck";
   };
 

pkgs/development/libraries/gmp/5.1.x.nix

@@ -6,10 +6,11 @@
 let inherit (lib) optional; in
 
 let self = stdenv.mkDerivation rec {
-  name = "gmp-5.1.3";
+  pname = "gmp";
+  version = "5.1.3";
 
   src = fetchurl { # we need to use bz2, others aren't in bootstrapping stdenv
-    urls = [ "mirror://gnu/gmp/${name}.tar.bz2" "ftp://ftp.gmplib.org/pub/${name}/${name}.tar.bz2" ];
+    urls = [ "mirror://gnu/gmp/gmp-${version}.tar.bz2" "ftp://ftp.gmplib.org/pub/gmp-${version}/gmp-${version}.tar.bz2" ];
     sha256 = "0q5i39pxrasgn9qdxzpfbwhh11ph80p57x6hf48m74261d97j83m";
   };
 

pkgs/development/libraries/gmp/6.x.nix

@@ -12,10 +12,11 @@
 let inherit (lib) optional; in
 
 let self = stdenv.mkDerivation rec {
-  name = "gmp-6.2.1";
+  pname = "gmp";
+  version = "6.2.1";
 
   src = fetchurl { # we need to use bz2, others aren't in bootstrapping stdenv
-    urls = [ "mirror://gnu/gmp/${name}.tar.bz2" "ftp://ftp.gmplib.org/pub/${name}/${name}.tar.bz2" ];
+    urls = [ "mirror://gnu/gmp/gmp-${version}.tar.bz2" "ftp://ftp.gmplib.org/pub/gmp-${version}/gmp-${version}.tar.bz2" ];
     sha256 = "0z2ddfiwgi0xbf65z4fg4hqqzlhv0cc6hdcswf3c6n21xdmk5sga";
   };