diff -Nru purify-2.0.0/debian/changelog purify-2.0.0/debian/changelog
--- purify-2.0.0/debian/changelog	2018-10-12 15:22:28.000000000 +0000
+++ purify-2.0.0/debian/changelog	2020-04-28 14:25:50.000000000 +0000
@@ -1,3 +1,11 @@
+purify (2.0.0-4+rpi1) bullseye-staging; urgency=medium
+
+  * export DEB_CXXFLAGS_MAINT_APPEND = -DSPDLOG_FMT_EXTERNAL -DFMT_HEADER_ONLY
+    to workaround issue in spdlog (worksaround: 953855).
+  * fix clean target.
+
+ -- Peter Michael Green <plugwash@raspbian.org>  Tue, 28 Apr 2020 14:25:50 +0000
+
 purify (2.0.0-4) unstable; urgency=medium
 
   * Disable measurement_operator test on aarch64 (Closes: #867273)
diff -Nru purify-2.0.0/debian/rules purify-2.0.0/debian/rules
--- purify-2.0.0/debian/rules	2018-10-12 06:42:00.000000000 +0000
+++ purify-2.0.0/debian/rules	2020-04-28 14:25:50.000000000 +0000
@@ -3,6 +3,8 @@
 
 #export DH_VERBOSE=1
 
+export DEB_CXXFLAGS_MAINT_APPEND = -DSPDLOG_FMT_EXTERNAL -DFMT_HEADER_ONLY
+
 CMAKE_FLAGS += -DDEB_BUILD_MULTIARCH=`dpkg-architecture -qDEB_BUILD_MULTIARCH`
 
 %:
@@ -12,3 +14,7 @@
 	cp -r /usr/include/eigen3 .
 	cd eigen3 && patch -p1 < ../debian/eigen3_LukePratley.patch
 	dh_auto_configure -- $(CMAKE_FLAGS)
+
+override_dh_auto_clean:
+	rm -rf eigen3
+	dh_auto_clean