diff -ur original/debian/rules patched/debian/rules
--- original/debian/rules
+++ patched/debian/rules
@@ -4,6 +4,11 @@
 
 DEB_HOST_MULTIARCH ?= $(shell dpkg-architecture -qDEB_HOST_MULTIARCH)
 
+# Avoid build failure due to missing symbols on architectures without libseccomp-dev.
+ifneq (,$(filter $(DEB_HOST_ARCH),alpha m68k sh4 sparc64))
+  export DPKG_GENSYMBOLS_CHECK_LEVEL = 0
+endif
+
 %:
 	dh ${@} --with autoreconf