diff --git a/pkgs/development/ocaml-modules/dolmen/loop.nix b/pkgs/development/ocaml-modules/dolmen/loop.nix
index 0b3ca565d81f..8d9b05ca7058 100644
--- a/pkgs/development/ocaml-modules/dolmen/loop.nix
+++ b/pkgs/development/ocaml-modules/dolmen/loop.nix
@@ -1,4 +1,6 @@
 {
+  lib,
+  ocaml,
   buildDunePackage,
   dolmen,
   dolmen_type,
@@ -11,6 +13,17 @@ buildDunePackage {
   pname = "dolmen_loop";
   inherit (dolmen) src version;
 
+  env =
+    # Fix build with gcc15
+    lib.optionalAttrs
+      (
+        lib.versionAtLeast ocaml.version "4.10" && lib.versionOlder ocaml.version "4.14"
+        || lib.versions.majorMinor ocaml.version == "5.0"
+      )
+      {
+        NIX_CFLAGS_COMPILE = "-std=gnu11";
+      };
+
   propagatedBuildInputs = [
     dolmen
     dolmen_type