Use the following make invocations to see different behaviors from variables or other make features:
$ make -f CheckDirExists.mk
$ make -f IncludeCheck.mk
$ make -f TargetOverride.mk
$ make -f DuplicatedTargets.mk target1
$ make -f TestVarExposure.mk VAR3=ble
$ make
$ make all
$ make test-check
$ make all dummy1 dummy2
# because of the '+' sign, the bla dir will be created
$ make --just-print
filter, lastword, patsubst, words
abspath, dir, notdir, realpath
Automatic variables, $*, $<, $^