diff --git a/pkgs/development/ocaml-modules/lablgtk/default.nix b/pkgs/development/ocaml-modules/lablgtk/default.nix
index f82548b1883..17f32ef3ede 100644
--- a/pkgs/development/ocaml-modules/lablgtk/default.nix
+++ b/pkgs/development/ocaml-modules/lablgtk/default.nix
@@ -10,18 +10,24 @@ let param =
       rev = version;
       sha256 = "sha256:0asib87c42apwf1ln8541x6i3mvyajqbarifvz11in0mqn5k7g7h";
     };
+    NIX_CFLAGS_COMPILE = null;
   } else if check "3.12" then {
     version = "2.18.5";
     src = fetchurl {
       url = "https://forge.ocamlcore.org/frs/download.php/1627/lablgtk-2.18.5.tar.gz";
       sha256 = "0cyj6sfdvzx8hw7553lhgwc0krlgvlza0ph3dk9gsxy047dm3wib";
     };
+    # Workaround build failure on -fno-common toolchains like upstream
+    # gcc-10. Otherwise build fails as:
+    #   ld: ml_gtktree.o:(.bss+0x0): multiple definition of
+    #     `ml_table_extension_events'; ml_gdkpixbuf.o:(.bss+0x0): first defined here
+    NIX_CFLAGS_COMPILE = "-fcommon";
   } else throw "lablgtk is not available for OCaml ${ocaml.version}";
 in
 
 stdenv.mkDerivation {
   pname = "lablgtk";
-  inherit (param) version src;
+  inherit (param) version src NIX_CFLAGS_COMPILE;
 
   nativeBuildInputs = [ pkg-config ocaml findlib ];
   buildInputs = [ gtk2 libgnomecanvas gtksourceview ];