Allow monster level adjustments in special levels

Add a new parameter to des.monster, m_lev_adj, which is a level
adjustment for the monster.  This only applies to the monster's
level, so basically only affects the spellcasting, it does not
change the monster's hit die or inventory.

Change one of the shamans in Orctown to be 3 levels higher.

dat/minetn-1.lua

@@ -130,8 +130,10 @@ for i=1,5 + math.random(1 - 1,1*10) do
    end
 end
 -- shamans can be hanging out in/near the temple
-for i=1,math.random(2 - 1,2*3) do
+-- one of the shamans is higher level
-   des.monster({ id = "orc shaman", coord = near_temple:rndcoord(0), peaceful=0 });
+for i=1,math.random(1,6) do
+   des.monster({ id = "orc shaman", coord = near_temple:rndcoord(0), peaceful=0,
+                 m_lev_adj = (i == 1) and 3 or 0 });
 end
 -- these are not such a big deal
 -- to run into outside the bars

doc/fixes3-7-0.txt

@@ -1588,6 +1588,7 @@ priest donation amounts are explicitly stated, randomized slightly, based on
 amulet of magical breathing increases power regeneration
 change some command keys, 'v' is now chronicle, 'V' is versionshort,
 	m-prefix 'V' is longer version, remove key binding of #history
+one orc-town shaman has a higher level, affecting spellcasting
 
 
 Fixes to 3.7.0-x General Problems Exposed Via git Repository

doc/lua.adoc

@@ -819,6 +819,7 @@ The hash parameter accepts the following keys:
 | stunned        | boolean |
 | confused       | boolean |
 | waiting        | boolean | monster will wait until hero gets next to it
+| m_lev_adj      | integer | monster's level adjustment
 | tail           | boolean | generate worm without a tail?
 | group          | boolean | generate a group of monsters?
 | adjacentok     | boolean | is adjacent location ok, if given one is not suitable?

include/sp_lev.h

@@ -145,6 +145,7 @@ typedef struct {
     schar peaceful, asleep;
     short female, invis, cancelled, revived, avenge, fleeing, blinded,
         paralyzed, stunned, confused, waiting;
+    short m_lev_adj;
     long seentraps;
     short has_invent;
     mmflags_nht mm_flags; /* makemon flags */

src/sp_lev.c

@@ -2165,6 +2165,14 @@ create_monster(monster *m, struct mkroom *croom)
             if (vampshifted(mtmp) && m->appear != M_AP_MONSTER)
                 (void) newcham(mtmp, &mons[mtmp->cham], NO_NC_FLAGS);
         }
+        if (m->m_lev_adj) {
+            if (mtmp->m_lev + m->m_lev_adj > 49)
+                mtmp->m_lev = 49;
+            else if (mtmp->m_lev + m->m_lev_adj < 0)
+                mtmp->m_lev = 0;
+            else
+                mtmp->m_lev += m->m_lev_adj;
+        }
         if (!(m->has_invent & DEFAULT_INVENT)) {
             /* guard against someone accidentally specifying e.g. quest nemesis
              * with custom inventory that lacks Bell or quest artifact but
@@ -3298,6 +3306,7 @@ lspo_monster(lua_State *L)
         tmpmons.stunned = get_table_boolean_opt(L, "stunned", FALSE);
         tmpmons.confused = get_table_boolean_opt(L, "confused", FALSE);
         tmpmons.waiting = get_table_boolean_opt(L, "waiting", FALSE);
+        tmpmons.m_lev_adj = get_table_int_opt(L, "m_lev_adj", 0);
         tmpmons.seentraps = 0; /* TODO: list of trap names to bitfield */
         keep_default_invent =
             get_table_boolean_opt(L, "keep_default_invent", -1);