gmpxx: remove appendToName to have a consistent package name for repology

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

@@ -12,7 +12,7 @@
 let inherit (lib) optional; in
 
 let self = stdenv.mkDerivation rec {
-  pname = "gmp";
+  pname = "gmp${lib.optionalString cxx "-with-cxx"}";
   version = "6.2.1";
 
   src = fetchurl { # we need to use bz2, others aren't in bootstrapping stdenv

pkgs/top-level/all-packages.nix

@@ -16930,7 +16930,7 @@ with pkgs;
   gmp5 = callPackage ../development/libraries/gmp/5.1.x.nix { };
   gmp6 = callPackage ../development/libraries/gmp/6.x.nix { };
   gmp = gmp6;
-  gmpxx = appendToName "with-cxx" (gmp.override { cxx = true; });
+  gmpxx = gmp.override { cxx = true; };
 
   #GMP ex-satellite, so better keep it near gmp
   mpfr = callPackage ../development/libraries/mpfr { };