frr: use elfutils instead of abandoned libelf

pkgs/servers/frr/clippy-helper.nix

@@ -8,7 +8,7 @@
 , flex
 , bison
 , pkg-config
-, libelf
+, elfutils
 , perl
 , python3
 
@@ -29,8 +29,9 @@ stdenv.mkDerivation rec {
   ];
 
   buildInputs = [
-    libelf
     python3
+  ] ++ lib.optionals (lib.meta.availableOn stdenv.hostPlatform elfutils) [
+    elfutils
   ];
 
   configureFlags = [

pkgs/servers/frr/default.nix

@@ -16,7 +16,7 @@
 , c-ares
 , json_c
 , libcap
-, libelf
+, elfutils
 , libunwind
 , libyang
 , net-snmp
@@ -118,7 +118,6 @@ stdenv.mkDerivation rec {
   buildInputs = [
     c-ares
     json_c
-    libelf
     libunwind
     libyang
     openssl
@@ -132,6 +131,8 @@ stdenv.mkDerivation rec {
     libcap
   ] ++ lib.optionals snmpSupport [
     net-snmp
+  ] ++ lib.optionals (lib.meta.availableOn stdenv.hostPlatform elfutils) [
+    elfutils
   ];
 
   # otherwise in cross-compilation: "configure: error: no working python version found"