+ # If no target specified, force "clean all" and disallow parallel build
+ ifeq ($(MAKECMDGOALS),)
+ MAKECMDGOALS := clean all
+ .NOTPARALLEL:
+ endif
+
+ # If one of the targets is to build, force "clean" beforehand and disallow parallel build
+ ifneq ($(findstring all, $(MAKECMDGOALS)),)
+ MAKECMDGOALS := clean $(MAKECMDGOALS)
+ .NOTPARALLEL:
+ endif