current_cpu
current_os
current_toolchain
default_toolchain
host_cpu
host_os
root_build_dir
root_gen_dir
root_out_dir
target_cpu
target_gen_dir
target_os
target_out_dir

----------------------------------------------------

[
	["constant", "current_cpu"],
	["constant", "current_os"],
	["constant", "current_toolchain"],
	["constant", "default_toolchain"],
	["constant", "host_cpu"],
	["constant", "host_os"],
	["constant", "root_build_dir"],
	["constant", "root_gen_dir"],
	["constant", "root_out_dir"],
	["constant", "target_cpu"],
	["constant", "target_gen_dir"],
	["constant", "target_os"],
	["constant", "target_out_dir"]
]
