Changed the #-of-arenas counters to uints -- no need to be insane about

this.  But added an overflow check just in case there is.

Got rid of the ushort macro.  It wasn't used anymore (it was only used
in the no-longer-exists off_t macro), and there's no plausible use for it.

Objects/obmalloc.c

@@ -213,9 +213,6 @@
 #undef  uchar
 #define uchar			unsigned char	/* assuming == 8 bits  */
 
-#undef  ushort
-#define ushort			unsigned short	/* assuming >= 16 bits */
-
 #undef  uint
 #define uint			unsigned int	/* assuming >= 16 bits */
 
@@ -235,7 +232,7 @@ struct pool_header {
 	block *freeblock;		/* pool's free list head         */
 	struct pool_header *nextpool;	/* next pool of this size class  */
 	struct pool_header *prevpool;	/* previous pool       ""        */
-	ulong arenaindex;		/* index into arenas of base adr */
+	uint arenaindex;		/* index into arenas of base adr */
 	uint szidx;			/* block size class index	 */
 	uint capacity;			/* pool capacity in # of blocks  */
 };
@@ -312,8 +309,8 @@ static poolp freepools = NULL;		/* free list for cached pools */
  * to the OS.
  */
 static uptr *arenas = NULL;
-static ulong narenas = 0;
-static ulong maxarenas = 0;
+static uint narenas = 0;
+static uint maxarenas = 0;
 
 /* Number of pools still available to be allocated in the current arena. */
 static uint nfreepools = 0;
@@ -330,7 +327,7 @@ dumpem(void *ptr)
 {
 	if (ptr)
 		printf("inserted new arena at %08x\n", ptr);
-	printf("# arenas %d\n", narenas);
+	printf("# arenas %u\n", narenas);
 	printf("was mine %lu wasn't mine %lu\n", wasmine, wasntmine);
 }
 #define INCMINE ++wasmine
@@ -403,8 +400,12 @@ new_arena(void)
 		 * XXX until after the PyMem_FREE(oldarenas) below completes.
 		 */
 		uptr *oldarenas;
-		int newmax = maxarenas + (maxarenas >> 1);
-		uptr *p = (uptr *)PyMem_MALLOC(newmax * sizeof(*arenas));
+		uptr *p;
+		uint newmax = maxarenas + (maxarenas >> 1);
+
+		if (newmax <= maxarenas)	/* overflow */
+			goto error;
+		p = (uptr *)PyMem_MALLOC(newmax * sizeof(*arenas));
 		if (p == NULL)
 			goto error;
 		memcpy(p, arenas, narenas * sizeof(*arenas));
@@ -417,7 +418,7 @@ new_arena(void)
 	/* Append the new arena address to arenas. */
 	assert(narenas < maxarenas);
 	arenas[narenas] = (uptr)bp;
-	++narenas;
+	++narenas;	/* can't overflow, since narenas < maxarenas before */
 	dumpem(bp);
 	return bp;