Given this Kconfig: config MY_STR string "A string"
The directive #if defined(CONFIG_MY_STR) will eval to true for the default empty string.
How to check if CONFIG_MY_STR is an empty string at compile time? Is it a better practice to use a second boolean value (e.g. CONFIG_USE_MY_STR) like the following? config MY_STR string "A string" depends on USE_MY_STR
