distinguish global variables that get written to savefile

The g? structs had a mix of variables that were written to
the savefile, and those that were not.

For better clarity and to distinguish those that end up in
the savefile, relocate some g? variables that get written
directly to the savefile into different structs.

This updates EDITLEVEL, although technically it probably
didn't need to, since savefile contents are not changing.

Details:

    gb.bases            -> svb.bases
    gb.bbubbles         -> svb.bbubbles
    gb.branches         -> svb.branches
    gc.context          -> svc.context
    gd.disco            -> svd.disco
    gd.dndest           -> svd.dndest
    gd.doors            -> svd.doors
    gd.doors_alloc      -> svd.doors_alloc
    gd.dungeon_topology -> svd.dungeon_topology
    gd.dungeons         -> svd.dungeons
    ge.exclusion_zones  -> sve.exclusion_zones
    gh.hackpid          -> svh.hackpid
    gi.inv_pos          -> svi.inv_pos
    gk.killer           -> svk.killer
    gl.lastseentyp      -> svl.lastseentyp
    gl.level            -> svl.level
    gl.level_info       -> svl.level_info
    gm.mapseenchn       -> svm.mapseenchn
    gm.moves            -> svm.moves
    gm.mvitals          -> svm.mvitals
    gn.n_dgns           -> svn.n_dgns
    gn.n_regions        -> svn.n_regions
    gn.nroom            -> svn.nroom
    go.oracle_cnt       -> svo.oracle_cnt
    gp.pl_character     -> svp.pl_character
    gp.pl_fruit         -> svp.pl_fruit
    gp.plname           -> svp.plname
    gp.program_state    -> svp.program_state
    gq.quest_status     -> svq.quest_status
    gr.rooms            -> svr.rooms
    gs.sp_levchn        -> svs.sp_levchn
    gs.spl_book         -> svs.spl_book
    gt.timer_id         -> svt.timer_id
    gt.tune             -> svt.tune
    gu.updest           -> svu.updest
    gx.xmax             -> svx.xmax
    gx.xmin             -> svx.xmin
    gy.ymax             -> svy.ymax
    gy.ymin             -> svy.ymin

Related note:
There are some pointer variables that are heads of chains that were not
moved from 'g?' to 'sv?', because they are not actually written to the
savefile directly, but the objects/monst/trap/lightsource/timer in the
chains they point to are. That can be changed, if desired.
Examples: gi.invent, gm.migrating_objs, gb.billobjs, gm.migrating_mons,
          gf.ftrap, gl.light_base, gt.timer_base

src/botl.c

@@ -58,7 +58,7 @@ do_statusline1(void)
     if (suppress_map_output())
         return strcpy(newbot1, "");
 
-    Strcpy(newbot1, gp.plname);
+    Strcpy(newbot1, svp.plname);
     if ('a' <= newbot1[0] && newbot1[0] <= 'z')
         newbot1[0] += 'A' - 'a';
     newbot1[10] = 0;
@@ -160,7 +160,7 @@ do_statusline2(void)
 
     /* time/move counter */
     if (flags.time)
-        Sprintf(tmmv, "T:%ld", gm.moves);
+        Sprintf(tmmv, "T:%ld", svm.moves);
     else
         tmmv[0] = '\0';
     tln = strlen(tmmv);
@@ -281,7 +281,7 @@ timebot(void)
     if (gb.bot_disabled)
         return;
     /* we're called when disp.time_botl is set and general disp.botl
-       is clear; disp.time_botl gets set whenever gm.moves changes value
+       is clear; disp.time_botl gets set whenever svm.moves changes value
        so there's no benefit in tracking previous value to decide whether
        to skip update; suppress_map_output() handles program_state.restoring
        and program_state.done_hup (tty hangup => no further output at all)
@@ -451,7 +451,7 @@ describe_level(
     int ret = 1;
 
     if (Is_knox(&u.uz)) {
-        Sprintf(buf, "%s", gd.dungeons[u.uz.dnum].dname);
+        Sprintf(buf, "%s", svd.dungeons[u.uz.dnum].dname);
         addbranch = FALSE;
     } else if (In_quest(&u.uz)) {
         Sprintf(buf, "Home %d", dunlev(&u.uz));
@@ -471,7 +471,7 @@ describe_level(
         ret = 0;
     }
     if (addbranch) {
-        Sprintf(eos(buf), ", %s", gd.dungeons[u.uz.dnum].dname);
+        Sprintf(eos(buf), ", %s", svd.dungeons[u.uz.dnum].dname);
         (void) strsubst(buf, "The ", "the ");
     }
     if (addspace)
@@ -769,7 +769,7 @@ bot_via_windowport(void)
     /*
      *  Player name and title.
      */
-    Strcpy(nb = buf, gp.plname);
+    Strcpy(nb = buf, svp.plname);
     nb[0] = highc(nb[0]);
     titl = !Upolyd ? rank() : pmname(&mons[u.umonnum], Ugender);
     i = (int) (strlen(buf) + sizeof " the " + strlen(titl) - sizeof "");
@@ -873,7 +873,7 @@ bot_via_windowport(void)
     gb.blstats[idx][BL_EXP].a.a_long = u.uexp;
 
     /* Time (moves) */
-    gb.blstats[idx][BL_TIME].a.a_long = gm.moves;
+    gb.blstats[idx][BL_TIME].a.a_long = svm.moves;
 
     /* Hunger */
     /* note: u.uhs is unsigned, and 3.6.1's STATUS_HILITE defined
@@ -1042,7 +1042,7 @@ stat_update_time(void)
     int fld = BL_TIME;
 
     /* Time (moves) */
-    gb.blstats[idx][fld].a.a_long = gm.moves;
+    gb.blstats[idx][fld].a.a_long = svm.moves;
     gv.valset[fld] = FALSE;
 
     eval_notify_windowport_field(fld, gv.valset, idx);
@@ -1298,17 +1298,17 @@ eval_notify_windowport_field(
     }
 
     /* Temporary? hack: moveloop()'s prolog for a new game sets
-     * gc.context.rndencode after the status window has been init'd,
+     * svc.context.rndencode after the status window has been init'd,
      * so $:0 has already been encoded and cached by the window
      * port.  Without this hack, gold's \G sequence won't be
      * recognized and ends up being displayed as-is for 'gu.update_all'.
      *
-     * Also, even if gc.context.rndencode hasn't changed and the
+     * Also, even if svc.context.rndencode hasn't changed and the
      * gold amount itself hasn't changed, the glyph portion of the
      * encoding may have changed if a new symset was put into effect.
      *
      *  \GXXXXNNNN:25
-     *  XXXX = the gc.context.rndencode portion
+     *  XXXX = the svc.context.rndencode portion
      *  NNNN = the glyph portion
      *  25   = the gold amount
      *
@@ -1316,10 +1316,10 @@ eval_notify_windowport_field(
      * not to honor an initial highlight, so force 'gu.update_all = TRUE'.
      */
     if (fld == BL_GOLD
-        && (gc.context.rndencode != oldrndencode
+        && (svc.context.rndencode != oldrndencode
             || gs.showsyms[COIN_CLASS + SYM_OFF_O] != oldgoldsym)) {
         gu.update_all = TRUE; /* chg = 2; */
-        oldrndencode = gc.context.rndencode;
+        oldrndencode = svc.context.rndencode;
         oldgoldsym = gs.showsyms[COIN_CLASS + SYM_OFF_O];
     }
 
@@ -2023,7 +2023,7 @@ status_eval_next_unhilite(void)
     struct istat_s *curr;
     long next_unhilite, this_unhilite;
 
-    gb.bl_hilite_moves = gm.moves; /* simplified; at one point we used to
+    gb.bl_hilite_moves = svm.moves; /* simplified; at one point we used to
                                     * try to encode fractional amounts for
                                     * multiple moves within same turn */
     /* figure out whether an unhilight needs to be performed now */
@@ -2276,7 +2276,7 @@ get_hilite(
                 txtstr = gb.blstats[idx][fldidx].val;
                 if (fldidx == BL_TITLE)
                     /* "<name> the <rank-title>", skip past "<name> the " */
-                    txtstr += (strlen(gp.plname) + sizeof " the " - sizeof "");
+                    txtstr += (strlen(svp.plname) + sizeof " the " - sizeof "");
                 if (hl->rel == TXT_VALUE && hl->textmatch[0]) {
                     if (fuzzymatch(hl->textmatch, txtstr, "\" -_", TRUE)) {
                         rule = hl;