diff --git a/pkgs/development/libraries/libsmi/default.nix b/pkgs/development/libraries/libsmi/default.nix
index 9b71a91efed2..14139d849dc7 100644
--- a/pkgs/development/libraries/libsmi/default.nix
+++ b/pkgs/development/libraries/libsmi/default.nix
@@ -9,6 +9,8 @@ stdenv.mkDerivation rec {
     sha256 = "1lslaxr2qcj6hf4naq5n5mparfhmswsgq4wa7zm2icqvvgdcq6pj";
   };
 
+  env.NIX_CFLAGS_COMPILE = "-std=gnu90";
+
   meta = with lib; {
     description = "A Library to Access SMI MIB Information";
     homepage = "https://www.ibr.cs.tu-bs.de/projects/libsmi/index.html";