Was being shown before locale was selected, so always using default
translation. Fixed by deferring the dialog, and also added an assert
for debug builds, if trying to access translated string too early.
- remove use of boost in src/Main/locale.cxx;
- add missing header <cstring> for std::strlen();
- replace NULL with nullptr;
- fix some broken indentation;
- other small readability improvements.
This function returns the preferred "locale"[1] according to user choice
and/or settings (i.e., it is influenced by --language if passed,
otherwise by current locale/system settings). The return value never has
an encoding part. It is the empty string if nothing could be found,
otherwise should look like fr_BE or it_IT.
[1] "language" term used in the function name for consistency with the
existing and related FGLocale::selectLanguage().
Windows and Mac implementations return a string without any encoding
specifier -> remove this specifier directly in the Unix/Linux
implementation for consistency.
Also do some small refactoring with the new static method
FGLocale::removeEncodingPart(). Slight difference with the previous
algorithm: if a '.' is found in the given locale spec, we assert() that
it is not the first character. The previous code in
FGLocale::findLocaleNode() used to consider such weird locale specs
starting with a dot as normal locale specs without any encoding part.
Note: the same change could be done where FGLocale::findLocaleNode()
looks for an underscore in order to prepare for the fallback
search (e.g., 'fr' after not finding translations for 'fr_FR').
Respect the user's language selection in the system settings, and try those languages in turn. If a language is explicitly specified, try that first regardless.
