Tests/RunCMake/add_custom_command/BadCommand.cmake - third_party/github.com/Kitware/CMake - Git at Google

 add_custom_command(OUTPUT "a" COMMAND "$<1:$<OUTPUT_CONFIG:a>>")
 add_custom_command(OUTPUT "b" COMMAND "$<1:$<COMMAND_CONFIG:b>>")
 add_custom_target(drive DEPENDS "a" "b")
	add_custom_command(OUTPUT "a" COMMAND "$<1:$<OUTPUT_CONFIG:a>>")
	add_custom_command(OUTPUT "b" COMMAND "$<1:$<COMMAND_CONFIG:b>>")
	add_custom_target(drive DEPENDS "a" "b")