Hmmm... I know I did it also in fpspreadsheet as well. But the problem is that once a unit has been added to "uses" it cannot be removed any more. So, when you add clocale to your package it will be in all applications built with your package. What if somebody does not need what clocale provides and does not want it? He only can modify the package sources (which is never good) or he can stop using your package (which is not good either).
I think it is the more versatile option to remove clocale from your package and to write a big note in the readme.txt or the docs of your application that a Linux/Unix user of your component should add clocale to his project's uses clause somewhere if he needs locale information.