Enhancement for Nightfox: set smb.subnum before launching message editor, thus

allowing external JS message editors to accurately use the bbs.smb_sub*
properties to get information about the current sub-board being posted to.

src/sbbs3/writemsg.cpp

@@ -409,6 +409,8 @@ bool sbbs_t::writemsg(const char *fname, const char *top, char *title, long mode
 		return(false); 
 	}
 
+	smb.subnum = subnum;	/* Allow JS msgeditors to use bbs.smb_sub* */
+
 	if(console&CON_RAW_IN) {
 		bprintf(text[EnterMsgNowRaw]
 			,(ulong)cfg.level_linespermsg[useron_level]*MAX_LINE_LEN);