--- a/debian/rules	2020-10-15 11:05:15.531617632 +0100
--- b/debian/rules	2020-10-21 12:50:16.231618188 +0100
@@ -154,6 +154,7 @@
 	# store probed configuration to support cross builds
 	for flavour in $(flavours); do \
 	  install -D -m 644 build-$$flavour/config.sh $(configdata)/config.sh.$$flavour; \
+	  $(PERL_TO_USE) -pi -e 's@\Q$(CURDIR)\E@/dummy/build/dir@g' $(configdata)/config.sh.$$flavour; \
 	  gzip -n $(configdata)/config.sh.$$flavour; \
 	done
 
@@ -208,6 +209,11 @@
 	# fix up generated headers
 	$(PERL_TO_USE) debian/fixheaders $(tmp)/$(lib)
 
+	# remove references to the build directory in some files
+	find $(tmp) \
+	  -path '*/CORE/config.h' -or -path '*/Config_heavy.pl' | \
+	    xargs -tr $(PERL_TO_USE) -pi -e 's@\Q$(CURDIR)\E@/dummy/build/dir@g'
+
 ifeq (,$(findstring nocheck,$(DEB_BUILD_OPTIONS)))
 	# Verify that the headers are usable
 	for ph in `< debian/headers sed -e 's/\.h$$/.ph/'`; do \