fix github issue #587 - incompatible save files

Save files from before the 'disambiguate WHACK' patch were not
necessarily compatible with ones after it, leading to potential
restore problems.

Comments in objclass.h (from before the patch) suggested that
inappropriate assumptions were being made about field layout.
This deliberately introduces new incompatibility and increments
EDITLEVEL to caused earlier save and bones files to be thrown
away.

Fixes #587

include/objects.h

@@ -21,6 +21,13 @@
 #define HARDGEM(n) (0)
 #endif
 
+/*
+ * Note...
+ *  OBJECTS() currently has 15 parameters; it more become needed, some
+ *  will need to be combined the way BITS() is used, because compilers
+ *  are allowed to impose a limit of 15.
+ */
+
 #if defined(OBJECTS_DESCR_INIT)
 #define OBJ(name,desc)  name, desc
 #define OBJECT(obj,bits,prp,sym,prob,dly,wt, \
@@ -28,21 +35,28 @@
 
 #elif defined(OBJECTS_INIT)
 #define COLOR_FIELD(X) X,
+/* notes: 'sub' was once a bitfield but got changed to separate schar when
+   it was overloaded to hold negative weapon skill indices; the first zero
+   is padding for oc_prediscovered which has variable init at run-time;
+   the second zero is oc_spare1 for padding between oc_tough and oc_dir */
 #define BITS(nmkn,mrg,uskn,ctnr,mgc,chrg,uniq,nwsh,big,tuf,dir,sub,mtrl) \
-  nmkn,mrg,uskn,0,mgc,chrg,uniq,nwsh,big,tuf,dir,mtrl,sub /*SCO cpp fodder*/
-#define OBJECT(obj,bits,prp,sym,prob,dly,wt,cost,sdam,ldam,oc1,oc2,nut,color,sn) \
+    nmkn,mrg,uskn,0,mgc,chrg,uniq,nwsh,big,tuf,0,dir,mtrl,sub /*cpp fodder*/
+#define OBJECT(obj,bits,prp,sym,prob,dly,wt,        \
+               cost,sdam,ldam,oc1,oc2,nut,color,sn) \
   { 0, 0, (char *) 0, bits, prp, sym, dly, COLOR_FIELD(color) prob, wt, \
     cost, sdam, ldam, oc1, oc2, nut }
 
 #elif defined(OBJECTS_ENUM)
 #define OBJ(name,desc)
-#define OBJECT(obj,bits,prp,sym,prob,dly,wt,cost,sdam,ldam,oc1,oc2,nut,color,sn) \
+#define OBJECT(obj,bits,prp,sym,prob,dly,wt,        \
+               cost,sdam,ldam,oc1,oc2,nut,color,sn) \
     sn
 
 #elif defined(DUMP_ENUMS)
 #define OBJ(name,desc)
-#define OBJECT(obj,bits,prp,sym,prob,dly,wt,cost,sdam,ldam,oc1,oc2,nut,color,sn) \
-    {sn, #sn}
+#define OBJECT(obj,bits,prp,sym,prob,dly,wt,        \
+               cost,sdam,ldam,oc1,oc2,nut,color,sn) \
+  { sn, #sn }
 
 #else
 #error Unproductive inclusion of objects.h
@@ -75,6 +89,7 @@ OBJECT(OBJ("strange object", NoDes),
 /* Note: for weapons that don't do an even die of damage (ex. 2-7 or 3-18)
    the extra damage is added on in weapon.c, not here! */
 
+/* weapon strike mode overloads the oc_dir field */
 #define P PIERCE
 #define S SLASH
 #define B WHACK