openvpn-auth-ldap: unpin LLVM17 (#373193)

pkgs/tools/networking/openvpn/openvpn-auth-ldap.nix

···
     })
   ];
 
+  # clang > 17 dropped support for `-export-dynamic` but `-rdynamic` does the
+  # same thing
+  postPatch = ''
+    substituteInPlace platform.m4 \
+      --replace-fail -export-dynamic -rdynamic
+  '';
+
   nativeBuildInputs = [
     autoreconfHook
     gnustep.base

pkgs/top-level/all-packages.nix

···
   openvpn_learnaddress = callPackage ../tools/networking/openvpn/openvpn_learnaddress.nix { };
 
   openvpn-auth-ldap = callPackage ../tools/networking/openvpn/openvpn-auth-ldap.nix {
-    inherit (llvmPackages_17) stdenv;
+    inherit (llvmPackages) stdenv;
   };
 
   namespaced-openvpn = python3Packages.callPackage ../tools/networking/namespaced-openvpn { };