diff --git a/pkgs/by-name/op/optar/package.nix b/pkgs/by-name/op/optar/package.nix
index 0e43288016fd..6f32f0fb7c62 100644
--- a/pkgs/by-name/op/optar/package.nix
+++ b/pkgs/by-name/op/optar/package.nix
@@ -27,6 +27,8 @@ stdenv.mkDerivation {
       --replace 'convert ' "${lib.getBin imagemagick}/bin/convert "
   '';
 
+  env.NIX_CFLAGS_COMPILE = toString [ "-Wno-error=implicit-int" ];
+
   preInstall = ''
     mkdir -p $out/bin
   '';