diff -Nru gambc-4.8.8/debian/changelog gambc-4.8.8/debian/changelog
--- gambc-4.8.8/debian/changelog	2018-01-12 01:58:03.000000000 +0000
+++ gambc-4.8.8/debian/changelog	2018-09-27 19:26:49.000000000 +0000
@@ -1,3 +1,10 @@
+gambc (4.8.8-3.1) unstable; urgency=medium
+
+  * Non-maintainer upload.
+  * Add the missing Breaks. (Closes: #879917)
+
+ -- Adrian Bunk <bunk@debian.org>  Thu, 27 Sep 2018 22:26:49 +0300
+
 gambc (4.8.8-3) unstable; urgency=medium
 
   * Some buildd/linting warning fixed
diff -Nru gambc-4.8.8/debian/control gambc-4.8.8/debian/control
--- gambc-4.8.8/debian/control	2018-01-12 01:57:13.000000000 +0000
+++ gambc-4.8.8/debian/control	2018-09-27 19:26:49.000000000 +0000
@@ -30,6 +30,7 @@
 Pre-Depends: ${misc:Pre-Depends}
 Depends: ${shlibs:Depends}, ${misc:Depends}
 Multi-Arch: same
+Breaks: libgambc4
 Replaces: libgambc4
 Description: Shared libraries for the Gambit interpreter and compiler
  The package includes .so, .c and .scm files, which are necessary to
@@ -40,6 +41,7 @@
 Architecture: any
 Depends: ${misc:Depends}, libgambit4 (= ${binary:Version})
 Multi-Arch: same
+Breaks: libgambc4-dev
 Replaces: libgambc4-dev
 Description: Header file and link for the Gambit shared library
  The package includes gambit.h and the libgambit.so, libgambitgsi.so