diff --git a/pkgs/by-name/ob/obconf/fix-implicit-declarations.patch b/pkgs/by-name/ob/obconf/fix-implicit-declarations.patch
new file mode 100644
index 000000000000..8db96f379034
--- /dev/null
+++ b/pkgs/by-name/ob/obconf/fix-implicit-declarations.patch
@@ -0,0 +1,37 @@
+diff --git a/src/appearance.c b/src/appearance.c
+index 4fb3f0c..7ae9cab 100644
+--- a/src/appearance.c
++++ b/src/appearance.c
+@@ -20,6 +20,7 @@
+ #include "main.h"
+ #include "tree.h"
+ #include "preview_update.h"
++#include <ctype.h>
+ 
+ static gboolean mapping = FALSE;
+ 
+diff --git a/src/desktops.h b/src/desktops.h
+index 1ba3e36..968595e 100644
+--- a/src/desktops.h
++++ b/src/desktops.h
+@@ -22,6 +22,7 @@
+ 
+ #include <gtk/gtk.h>
+ 
++void desktops_setup_tab();
+ void desktops_setup_num(GtkWidget *w);
+ void desktops_setup_names(GtkWidget *w);
+ 
+diff --git a/src/main.c b/src/main.c
+index d7e3446..fdfae54 100644
+--- a/src/main.c
++++ b/src/main.c
+@@ -28,6 +28,8 @@
+ #include "dock.h"
+ #include "preview_update.h"
+ #include "gettext.h"
++#include "desktops.h"
++#include "moveresize.h"
+ 
+ #include <gdk/gdkx.h>
+ #define SN_API_NOT_YET_FROZEN
diff --git a/pkgs/by-name/ob/obconf/package.nix b/pkgs/by-name/ob/obconf/package.nix
index 9b233017b4ea..603879bfbe85 100644
--- a/pkgs/by-name/ob/obconf/package.nix
+++ b/pkgs/by-name/ob/obconf/package.nix
@@ -23,6 +23,8 @@ stdenv.mkDerivation (finalAttrs: {
     hash = "sha256-qwm66VA/ueRMFtSUcrmuObNkz+KYgWRnmR7TnQwpxiE=";
   };
 
+  patches = [ ./fix-implicit-declarations.patch ];
+
   nativeBuildInputs = [
     autoreconfHook
     pkg-config