Revert "Moved sex_change_ok to instance_globals."

This reverts commit ee22210a68.

include/decl.h

@@ -464,11 +464,6 @@ struct instance_globals {
     /* pickup.c */
     int oldcap; /* last encumberance */
 
-    /* polyself.c */
-    int sex_change_ok; /* controls whether taking on new form or becoming new
-                          man can also change sex (ought to be an arg to
-                          polymon() and newman() instead) */
-
     /* potion.c */
     boolean notonhead; /* for long worms */
     int potion_nothing;

src/decl.c

@@ -348,9 +348,6 @@ const struct instance_globals g_init = {
     /* pickup.c */
     0,  /* oldcap */
 
-    /* polyself.c */
-    0, /* sex_change_ok */
-
     /* potion.c */
     FALSE, /* notonhead */
     UNDEFINED_VALUE, /* potion_nothing */

src/polyself.c

@@ -33,6 +33,10 @@ STATIC_DCL void NDECL(polysense);
 STATIC_VAR const char no_longer_petrify_resistant[] =
     "No longer petrify-resistant, you";
 
+/* controls whether taking on new form or becoming new man can also
+   change sex (ought to be an arg to polymon() and newman() instead) */
+STATIC_VAR int sex_change_ok = 0;
+
 /* update the youmonst.data structure pointer and intrinsics */
 void
 set_uasmon()
@@ -292,7 +296,7 @@ newman()
         u.ulevelmax = newlvl;
     u.ulevel = newlvl;
 
-    if (g.sex_change_ok && !rn2(10))
+    if (sex_change_ok && !rn2(10))
         change_sex();
 
     adjabil(oldlvl, (int) u.ulevel);
@@ -569,14 +573,14 @@ int psflags;
     /* The below polyok() fails either if everything is genocided, or if
      * we deliberately chose something illegal to force newman().
      */
-    g.sex_change_ok++;
+    sex_change_ok++;
     if (!polyok(&mons[mntmp]) || (!forcecontrol && !rn2(5))
         || your_race(&mons[mntmp])) {
         newman();
     } else {
         (void) polymon(mntmp);
     }
-    g.sex_change_ok--; /* reset */
+    sex_change_ok--; /* reset */
 
 made_change:
     new_light = emits_light(youmonst.data);
@@ -646,7 +650,7 @@ int mntmp;
         if (!flags.female)
             dochange = TRUE;
     } else if (!is_neuter(&mons[mntmp]) && mntmp != u.ulycn) {
-        if (g.sex_change_ok && !rn2(10))
+        if (sex_change_ok && !rn2(10))
             dochange = TRUE;
     }