I found the following self-reference which is automatically identified as circular-loop by the Makefileparser, even though it should be valid. It is a dumb way of using +=
DIRS := $(DIRS) $(filter-out $(DIRS), configure)
DIRS := $(DIRS) $(filter-out $(DIRS), $(wildcard *App))
DIRS := $(DIRS) $(filter-out $(DIRS), $(wildcard iocBoot))
This works correctly in GNU Make.
