--- a/make/InitSupport.gmk	Thu Jun 14 11:22:04 2018 +0200
+++ b/make/InitSupport.gmk	Thu Jun 14 11:46:53 2018 +0200
@@ -456,6 +456,9 @@
 	)
   endef
 
+  # Failure logs are only supported for "parallel" main targets, not the
+  # (trivial) sequential make targets (such as clean and reconfigure),
+  # since the failure-logs directory creation will conflict with clean.
   define PrepareFailureLogs
 	$(RM) -r $(MAKESUPPORT_OUTPUTDIR)/failure-logs 2> /dev/null && \
 	$(MKDIR) -p $(MAKESUPPORT_OUTPUTDIR)/failure-logs