Use the translation map for unix system locale

[CupnPlateGames]

This patchs looks for an acceptable entry when using the System locale (from environment variables) to have the same behaviour as when selecting a locale explicitely.

How to reproduce, before the patch:

• install a locale on your system that is not English and supported by Warzone 2100, set it as your system locale (for example fr_FR, de_DE or ru_RU)
• relog, check your locale with locale
• Run the game, it should be translated when you select the language in the settings, but still be in English with System locale

How to test, after the patch:

• With your system still in the non-English locale
• Run the game, it should be translated with System locale
• You can try an alternative locale like de_BE and it should still be in German (unless the locale de_DE is not installed which is an other issue)