diff --git a/pkgs/applications/misc/keepassx/community.nix b/pkgs/applications/misc/keepassx/community.nix
index 55ed1fe148b..4daa1938aba 100644
--- a/pkgs/applications/misc/keepassx/community.nix
+++ b/pkgs/applications/misc/keepassx/community.nix
@@ -34,6 +34,8 @@ stdenv.mkDerivation rec {
     sha256 = "1zch1qbqgphhp2p2kvjlah8s337162m69yf4y00kcnfb3539ii5f";
   };
 
+  NIX_CFLAGS_COMPILE = stdenv.lib.optionalString stdenv.cc.isClang "-Wno-old-style-cast";
+
   patches = [ ./darwin.patch ];
 
   cmakeFlags = [