New M32Script command "getspritelinktype" <spritenum> <<linktypevar>>.

This get into the writable variable the "linking type" of the sprite with index
<spritenum>.  The result is a bit field of ORed values:
 1: lotag has linking semantics
 2: hitag
 4: extra, 8: xvel, 16: yvel, 32: zvel, 64: owner  (custom only)

Custom setting about which sprites have what kind of linking can be programmed
via EVENT_LINKTAGS: it receives a sprite index as the 'current sprite' and is
supposed to return the bit field in RETURN.

An example which lists sprites and their linking hi- and lotags is provided in
the state 'listusedtags' in a.m32.

git-svn-id: https://svn.eduke32.com/eduke32@2590 1a8010ca-5511-0410-912e-c29ae57300e0

polymer/eduke32/samples/a.m32

@@ -1268,6 +1268,22 @@ defstate chselshade
     }
 ends
 
+defstate listusedtags
+    for i allsprites
+    {
+        getspritelinktype i k
+
+        ifn k 0
+        {
+            ife k 1
+                qsprintf TQUOTE "sprite %d lotag %d" i sprite[i].lotag
+            else ife k 2
+                qsprintf TQUOTE "sprite %d hitag %d" i sprite[i].hitag
+            quote TQUOTE
+        }
+    }
+ends
+
 ////////// USER AREA //////////
 
 // key settings

polymer/eduke32/source/m32def.c

@@ -303,13 +303,14 @@ const char *keyw[] =
     "ifaimingsector",
     "ifinteractive",
 
-// BUILD functions
+// Mostly BUILD functions
     "resetkey",
     "setkey",
     "insertsprite",
     "dupsprite",
     "tdupsprite",
     "deletesprite",
+    "getspritelinktype",  // not BUILD
     "lastwall",
     "updatecursectnum",
     "updatesector",
@@ -2845,6 +2846,7 @@ repeatcase:
         return 0;
 
     case CON_SQRT:
+    case CON_GETSPRITELINKTYPE:
     {
         // syntax sqrt <invar> <outvar>
         // gets the sqrt of invar into outvar

polymer/eduke32/source/m32def.h

@@ -458,6 +458,7 @@ enum ScriptKeywords_t
     CON_DUPSPRITE,
     CON_TDUPSPRITE,
     CON_DELETESPRITE,
+    CON_GETSPRITELINKTYPE,
     CON_LASTWALL,
     CON_UPDATECURSECTNUM,
     CON_UPDATESECTOR,

polymer/eduke32/source/m32exec.c

@@ -1733,6 +1733,16 @@ badindex:
             }
             continue;
 
+        case CON_GETSPRITELINKTYPE:
+            insptr++;
+            {
+                int32_t spritenum=Gv_GetVarX(*insptr++), resvar = *insptr++;
+
+                X_ERROR_INVALIDSPRI(spritenum);
+                Gv_SetVarX(resvar, taglab_linktags(1, spritenum));
+            }
+            continue;
+
         case CON_LASTWALL:
             insptr++;
             {