diff -pruN 1.1.1.deb-2/debian/changelog 1.1.1.deb-2ubuntu2/debian/changelog
--- 1.1.1.deb-2/debian/changelog	2022-11-10 10:21:48.000000000 +0000
+++ 1.1.1.deb-2ubuntu2/debian/changelog	2023-01-26 11:38:32.000000000 +0000
@@ -1,3 +1,9 @@
+coccinelle (1.1.1.deb-2ubuntu2) lunar; urgency=medium
+
+  * Limit to parallel=1 on armhf and riscv64, to fix a build failure.
+
+ -- Gianfranco Costamagna <locutusofborg@debian.org>  Thu, 26 Jan 2023 12:38:32 +0100
+
 coccinelle (1.1.1.deb-2) unstable; urgency=medium
 
   * d/rules: force configuration for python3. Thanks to Uwe Kleine-König
diff -pruN 1.1.1.deb-2/debian/rules 1.1.1.deb-2ubuntu2/debian/rules
--- 1.1.1.deb-2/debian/rules	2022-11-10 10:21:48.000000000 +0000
+++ 1.1.1.deb-2ubuntu2/debian/rules	2023-01-26 11:38:32.000000000 +0000
@@ -21,7 +21,14 @@ endif
 export FORCE_SOURCE_DATE = 1
 
 %:
+ifneq (,$(filter armhf riscv64, $(DEB_HOST_ARCH)))
+        # Build fails with out-of-memory on Ubuntu's s390x builders.
+        # Setting `ggc-min-expand=10` doesn't solve this.
+        # For now, reduce number of parallel jobs.
+	dh $@ --with ocaml,python3,autoreconf --max-parallel=1
+else
 	dh $@ --with ocaml,python3,autoreconf
+endif
 
 override_dh_auto_configure:
 	./configure $(CONFIG_FLAGS)