Basic build
	make config T=x86_64-default-linuxapp-gcc && make
Build commands
	config      get configuration from target template (T=)
	all         same as build (default rule)
	build       build in a configured directory
	clean       remove files but keep configuration
	install     build many targets (wildcard allowed) in fixed directories
	uninstall   remove all installed targets
Build variables
	CROSS            toolchain prefix
	EXTRA_CPPFLAGS   preprocessor options
	EXTRA_CFLAGS     compiler options
	EXTRA_LDFLAGS    linker options
	RTE_KERNELDIR    linux headers path
	V   verbose
	D   debug dependencies
	O   output directory (default: build/)   - cannot be used with install
	T   target template (install default: *) - used with config or install
			format: <arch-machine-execenv-toolchain>
			templates in config/defconfig_*