diff -Nru tf-4.0s1/debian/changelog tf-4.0s1/debian/changelog
--- tf-4.0s1/debian/changelog	2018-05-03 14:19:32.000000000 +0000
+++ tf-4.0s1/debian/changelog	2020-07-23 09:40:24.000000000 +0000
@@ -1,8 +1,8 @@
-tf (1:4.0s1-20build1) cosmic; urgency=medium
+tf (1:4.0s1-21) unstable; urgency=medium
 
-  * No-change rebuild for ncurses soname changes.
+  * Fix build with gcc-10 (Closes: Bug#957871)
 
- -- Matthias Klose <doko@ubuntu.com>  Thu, 03 May 2018 14:19:32 +0000
+ -- Jan Niehusmann <jan@debian.org>  Thu, 23 Jul 2020 11:40:24 +0200
 
 tf (1:4.0s1-20) unstable; urgency=medium
 
diff -Nru tf-4.0s1/debian/patches/debian-changes tf-4.0s1/debian/patches/debian-changes
--- tf-4.0s1/debian/patches/debian-changes	2017-05-22 14:29:16.000000000 +0000
+++ tf-4.0s1/debian/patches/debian-changes	2020-07-23 09:40:24.000000000 +0000
@@ -757,6 +757,17 @@
  
      /* If lpflag is on and we got a partial line from the fg world,
       * assume the line is a prompt.
+--- tf-4.0s1.orig/src/socket.h
++++ tf-4.0s1/src/socket.h
+@@ -13,7 +13,7 @@
+ #define SOCK_RECV	0
+ #define SOCK_SEND	1
+ 
+-struct World   *world_decl;	/* declares struct World */
++struct World;	/* declares struct World */
+ 
+ extern Aline *incoming_text;
+ extern int quit_flag;
 --- tf-4.0s1.orig/src/tf.1.catman
 +++ tf-4.0s1/src/tf.1.catman
 @@ -152,6 +152,8 @@ TF(1)