C version of chk_ar() now supports the DOS keyword...

The "DOS" ARS keyword was always evaluating to false, on all platforms, for the C version of chk_ar(), which is used for populating JS *_area objects and for the User.compare_ars() implementation.

Unfortunately, the startup (sbbs.ini) "NO_DOS" option is not recognized here (yet), so it'll report true (e.g. for Win64 or Linux systems with DOSemu) even if/when the NO_DOS option is set.

src/sbbs3/userdat.c

@@ -1725,7 +1725,11 @@ static BOOL ar_exp(scfg_t* cfg, uchar **ptrptr, user_t* user, client_t* client)
 				#endif
 				break;
 			case AR_DOS:
-				result=not;
+				#if defined(_WIN32) || (defined(__linux__) && defined(USE_DOSEMU)) || defined(__FreeBSD__)
+					result=!not;
+				#else
+					result=not;
+				#endif
 				break;
 			case AR_WIN32:
 				#ifndef _WIN32