couchdb: fix eval for cross-compilation

Use erlangR22 for the build platform.
Requires buildPackages in top-level due to no splicing at that level.

pkgs/servers/http/couchdb/3.nix

@@ -1,5 +1,5 @@
 { lib, stdenv, fetchurl, erlang, icu, openssl, spidermonkey_91
-, coreutils, bash, makeWrapper, python3, nixosTests }:
+, coreutils, bash, python3, nixosTests }:
 
 stdenv.mkDerivation rec {
   pname = "couchdb";
@@ -13,7 +13,10 @@ stdenv.mkDerivation rec {
     sha256 = "sha256-acn9b4ATNVf2igLpLdpypP1kbWRvQp9Fu4Mpow+C8g4=";
   };
 
-  buildInputs = [ erlang icu openssl spidermonkey_91 (python3.withPackages(ps: with ps; [ requests ]))];
+  nativeBuildInputs = [
+    erlang
+  ];
+  buildInputs = [ icu openssl spidermonkey_91 (python3.withPackages(ps: with ps; [ requests ]))];
   postPatch = ''
     substituteInPlace src/couch/rebar.config.script --replace '/usr/include/mozjs-91' "${spidermonkey_91.dev}/include/mozjs-91"
     patchShebangs bin/rebar

pkgs/top-level/all-packages.nix

@@ -22332,7 +22332,7 @@ with pkgs;
   codeowners = callPackage ../development/tools/codeowners { };
 
   couchdb3 = callPackage ../servers/http/couchdb/3.nix {
-    erlang = erlangR22;
+    erlang = buildPackages.erlangR22;
   };
 
   dcnnt = python3Packages.callPackage ../servers/dcnnt { };