Make wxLanguageInfo::GetLocaleName() consistent across platforms

Check that the locale can be indeed set to the given string in Unix
version too, there doesn't seem to be any good reason to do it for MSW
only.

src/common/intl.cpp

@@ -205,7 +205,14 @@ wxString wxLanguageInfo::GetLocaleName() const
     return CanSetLocale(locale) ? locale : wxString();
 }
 
-#endif // __WINDOWS__
+#else // !__WINDOWS__
+
+wxString wxLanguageInfo::GetLocaleName() const
+{
+    return CanSetLocale(CanonicalName) ? CanonicalName : wxString();
+}
+
+#endif // __WINDOWS__/!__WINDOWS__
 
 // ----------------------------------------------------------------------------
 // wxLocale