Subject: Avoid build failures on powerful machines

+++ perl-5.34.0/debian/rules
@@ -115,11 +115,11 @@
 	if [ "$*" = "shared" ]; then \
 	  ln -s libperl.so.$(fullversion) build-$*/libperl.so.$(version); \
 	  ln -s libperl.so.$(version) build-$*/libperl.so; \
-	  dh_auto_build --builddirectory=build-$* -- SHRPLDFLAGS='$$(LDDLFLAGS) -Wl,-soname,libperl.so.$(version)'; \
+	  dh_auto_build --no-parallel --builddirectory=build-$* -- SHRPLDFLAGS='$$(LDDLFLAGS) -Wl,-soname,libperl.so.$(version)'; \
 	elif [ "$*" = "debug" ]; then \
-	  dh_auto_build --builddirectory=build-$* -- perl; \
+	  dh_auto_build --no-parallel --builddirectory=build-$* -- perl; \
 	else \
-	  dh_auto_build --builddirectory=build-$*; \
+	  dh_auto_build --no-parallel --builddirectory=build-$*; \
 	fi
 	touch $@