diff --git a/pkgs/by-name/mo/molden/package.nix b/pkgs/by-name/mo/molden/package.nix
index 12959c85825a..38f529d426e0 100644
--- a/pkgs/by-name/mo/molden/package.nix
+++ b/pkgs/by-name/mo/molden/package.nix
@@ -27,8 +27,8 @@ stdenv.mkDerivation rec {
 
   patches = [ ./dont_register_file_types.patch ];
 
-  # fix build with GCC 14
-  env.NIX_CFLAGS_COMPILE = "-Wno-implicit-function-declaration -Wno-implicit-int -Wno-return-mismatch";
+  # fix build with GCC 14+
+  env.NIX_CFLAGS_COMPILE = "-Wno-implicit-function-declaration -Wno-implicit-int -Wno-return-mismatch -std=gnu17";
 
   postPatch = ''
     substituteInPlace ./makefile --replace '-L/usr/X11R6/lib'  "" \