Make extended commands return defined flags

Instead of returning 0 or 1, we'll now use ECMD_OK or ECMD_TURN.
These have the same meaning as the hardcoded numbers; ECMD_TURN
means the command uses a turn.

In future, could add eg. a flag denoting "user cancelled command"
or "command failed", and should clear eg. the cmdq.

Mostly this was simply replacing return values with the defines
in the extended commands, so hopefully I didn't break anything.

src/write.c

@@ -114,18 +114,18 @@ dowrite(struct obj *pen)
 
     if (nohands(g.youmonst.data)) {
         You("need hands to be able to write!");
-        return 0;
+        return ECMD_OK;
     } else if (Glib) {
         pline("%s from your %s.", Tobjnam(pen, "slip"),
               fingers_or_gloves(FALSE));
         dropx(pen);
-        return 1;
+        return ECMD_TIME;
     }
 
     /* get paper to write on */
     paper = getobj("write on", write_ok, GETOBJ_NOFLAGS);
     if (!paper)
-        return 0;
+        return ECMD_OK;
     /* can't write on a novel (unless/until it's been converted into a blank
        spellbook), but we want messages saying so to avoid "spellbook" */
     typeword = (paper->otyp == SPE_NOVEL)
@@ -136,19 +136,19 @@ dowrite(struct obj *pen)
     if (Blind) {
         if (!paper->dknown) {
             You("don't know if that %s is blank or not.", typeword);
-            return 0;
+            return ECMD_OK;
         } else if (paper->oclass == SPBOOK_CLASS) {
             /* can't write a magic book while blind */
             pline("%s can't create braille text.",
                   upstart(ysimple_name(pen)));
-            return 0;
+            return ECMD_OK;
         }
     }
     paper->dknown = 1;
     if (paper->otyp != SCR_BLANK_PAPER && paper->otyp != SPE_BLANK_PAPER) {
         pline("That %s is not blank!", typeword);
         exercise(A_WIS, FALSE);
-        return 1;
+        return ECMD_TIME;
     }
 
     /* what to write */
@@ -156,7 +156,7 @@ dowrite(struct obj *pen)
     getlin(qbuf, namebuf);
     (void) mungspaces(namebuf); /* remove any excess whitespace */
     if (namebuf[0] == '\033' || !namebuf[0])
-        return 1;
+        return ECMD_TIME;
     nm = namebuf;
     if (!strncmpi(nm, "scroll ", 7))
         nm += 7;
@@ -213,21 +213,21 @@ dowrite(struct obj *pen)
     }
 
     There("is no such %s!", typeword);
-    return 1;
+    return ECMD_TIME;
  found:
 
     if (i == SCR_BLANK_PAPER || i == SPE_BLANK_PAPER) {
         You_cant("write that!");
         pline("It's obscene!");
-        return 1;
+        return ECMD_TIME;
     } else if (i == SPE_BOOK_OF_THE_DEAD) {
         pline("No mere dungeon adventurer could write that.");
-        return 1;
+        return ECMD_TIME;
     } else if (by_descr && paper->oclass == SPBOOK_CLASS
                && !objects[i].oc_name_known) {
         /* can't write unknown spellbooks by description */
         pline("Unfortunately you don't have enough information to go on.");
-        return 1;
+        return ECMD_TIME;
     }
 
     /* KMH, conduct */
@@ -244,7 +244,7 @@ dowrite(struct obj *pen)
     if (pen->spe < basecost / 2) {
         Your("marker is too dry to write that!");
         obfree(new_obj, (struct obj *) 0);
-        return 1;
+        return ECMD_TIME;
     }
 
     /* we're really going to write now, so calculate cost
@@ -265,7 +265,7 @@ dowrite(struct obj *pen)
             useup(paper);
         }
         obfree(new_obj, (struct obj *) 0);
-        return 1;
+        return ECMD_TIME;
     }
     pen->spe -= actualcost;
 
@@ -314,7 +314,7 @@ dowrite(struct obj *pen)
             useup(paper);
         }
         obfree(new_obj, (struct obj *) 0);
-        return 1;
+        return ECMD_TIME;
     }
     /* can write scrolls when blind, but requires luck too;
        attempts to write books when blind are caught above */
@@ -327,7 +327,7 @@ dowrite(struct obj *pen)
         You("fail to write the scroll correctly and it disappears.");
         useup(paper);
         obfree(new_obj, (struct obj *) 0);
-        return 1;
+        return ECMD_TIME;
     }
 
     /* useup old scroll / spellbook */
@@ -357,7 +357,7 @@ dowrite(struct obj *pen)
                                   The(aobjnam(new_obj, "slip")),
                                   (const char *) 0);
     nhUse(new_obj); /* try to avoid complaint about dead assignment */
-    return 1;
+    return ECMD_TIME;
 }
 
 /* most book descriptions refer to cover appearance, so we can issue a