Fix: certain monster steeds should only be ridden by certain monster riders.

For the player, only as a Drow can you ride spiders or cave lizards, or
only as an Orc can you ride a warg, and so on. Monster rider/steed pairs
didn't have this restriction, which seemed incorrect. This commit
addresses this, and brings monster rider/steed pairs to be more inline
with what the player can ride or not ride.

Author: k21971

doc/evilhack-changelog.md

@@ -3398,4 +3398,6 @@ The following changes to date are:
 - Fix: various monsters showing as having claws when they don't
 - Fix: update to last commit (claws)
 - Hippocrates (Healer quest leader) additional gear
+- Fix: certain monster steeds should only be ridden by certain monster
+  riders
 

include/mondata.h

@@ -551,7 +551,7 @@
      && !(mon)->mtame && (mon) != u.ustuck && !(mon)->mpeaceful              \
      && !(mon)->mtrapped && (mon)->mcanmove && !(mon)->msleeping             \
      && !is_shapeshifter((mon)->data) && !is_were((mon)->data)               \
-     && !(mon)->isshk && (mon)->data->mlet != S_DOG && (mon)->cham == NON_PM \
+     && !(mon)->isshk && (mon)->cham == NON_PM                               \
      && !((mon)->mstrategy & STRAT_WAITFORU))
 
 /* Used for conduct with corpses, tins, and digestion attacks */

src/steed.c

@@ -94,6 +94,18 @@ struct monst *rider;
         if (nmon == rider)
             nmon = rider->nmon;
         /* criteria for an acceptable steed */
+        if (!is_drow(rider->data) && is_spider(steed->data))
+            continue;
+        if (!is_drow(rider->data)
+            && (steed->data == &mons[PM_CAVE_LIZARD]
+                || steed->data == &mons[PM_LARGE_CAVE_LIZARD]))
+            continue;
+        if (!is_orc(rider->data) && steed->data == &mons[PM_WARG])
+            continue;
+        if (!(rider->data == &mons[PM_CAVEMAN]
+              || rider->data == &mons[PM_CAVEWOMAN])
+            && steed->data == &mons[PM_SABER_TOOTHED_TIGER])
+            continue;
         if (monnear(rider, steed->mx, steed->my) && mon_can_be_ridden(steed)
             && !steed->ridden_by) {
             break;