diff --git a/pkgs/development/lisp-modules/nix-cl.nix b/pkgs/development/lisp-modules/nix-cl.nix
index e97cc9892830..619a6144c5de 100644
--- a/pkgs/development/lisp-modules/nix-cl.nix
+++ b/pkgs/development/lisp-modules/nix-cl.nix
@@ -220,8 +220,12 @@ let
       javaLibs = lib.optionals isJVM args.javaLibs or [];
     in {
       pname = "${args.pkg.pname}-${args.pname}";
-      src = if builtins.length (args.patches or []) > 0
-            then pkgs.applyPatches { inherit (args) src patches; }
+      src = if args?patches || args?postPatch
+            then pkgs.applyPatches {
+              inherit (args) src;
+              patches = args.patches or [];
+              postPatch = args.postPatch or "";
+            }
             else args.src;
       patches = [];
       inherit javaLibs;
diff --git a/pkgs/development/lisp-modules/packages.nix b/pkgs/development/lisp-modules/packages.nix
index 2ce4fdda19a9..422b33a8aae8 100644
--- a/pkgs/development/lisp-modules/packages.nix
+++ b/pkgs/development/lisp-modules/packages.nix
@@ -75,6 +75,13 @@ let
     };
   };
 
+  cl-gobject-introspection = super.cl-gobject-introspection.overrideLispAttrs (o: {
+    postPatch = ''
+      substituteInPlace src/init.lisp \
+        --replace sb-ext::set-floating-point-modes sb-int:set-floating-point-modes
+    '';
+  });
+
   jzon = super.com_dot_inuoe_dot_jzon;
 
   cl-notify = build-asdf-system {