Use setlocale() to get the current locale.

Use setlocale() to get the current locale.

This:

	1) should work on Windows;

	2) reflects what the C environment is actually set up to use,
	   rather than what the environment variables for locale are
	   set up to use - C programs default to the C locale and only
	   pick up the setting from the environment variables etc. if
	   you explicitly request the system locale with a setlocale()
	   call.

Change-Id: Iee064237e70501a5450d4daa9ab849391f200efd
Reviewed-on: https://code.wireshark.org/review/6195
Reviewed-by: Guy Harris <guy@alum.mit.edu>