diff --git a/pkgs/by-name/gn/gnu-cim/package.nix b/pkgs/by-name/gn/gnu-cim/package.nix
index bf2835959ff1..b2c339d45a39 100644
--- a/pkgs/by-name/gn/gnu-cim/package.nix
+++ b/pkgs/by-name/gn/gnu-cim/package.nix
@@ -29,7 +29,13 @@ stdenv.mkDerivation rec {
     done
   '';
 
-  env.CFLAGS = lib.optionalString stdenv.cc.isClang "-Wno-return-type -Wno-error=implicit-function-declaration -Wno-error=implicit-int";
+  # lib.escapeShellArgs does not work
+  env.CFLAGS = lib.concatStringsSep " " [
+    "-Wno-error=implicit-function-declaration"
+    "-Wno-error=implicit-int"
+    "-Wno-error=return-mismatch"
+    "-Wno-error=incompatible-pointer-types"
+  ];
 
   doCheck = true;