diff --git a/pkgs/applications/science/math/symmetrica/default.nix b/pkgs/applications/science/math/symmetrica/default.nix
index d6ec352d32a2..f215ec0037d4 100644
--- a/pkgs/applications/science/math/symmetrica/default.nix
+++ b/pkgs/applications/science/math/symmetrica/default.nix
@@ -23,6 +23,10 @@ stdenv.mkDerivation rec {
     autoreconfHook
   ];
 
+  # clang warning: passing arguments to '...' without a prototype is deprecated
+  # in all versions of C and is not supported in C23.
+  CFLAGS = "-std=c99 -Wno-deprecated-non-prototype";
+
   enableParallelBuilding = true;
 
   meta = with lib; {