sizeof knows better than earthling

Reference: /n/sources/patch/applied/malloclong
Date: Wed Feb 23 18:01:19 CET 2005

--- /sys/src/libc/port/malloc.c	Wed Feb 23 18:00:17 2005
+++ /sys/src/libc/port/malloc.c	Wed Feb 23 18:00:13 2005
@@ -42,9 +42,9 @@
 static void*
 sbrkalloc(ulong n)
 {
-	long *x;
+	ulong *x;
 
-	n += 8;	/* two longs for us */
+	n += 2*sizeof(ulong);	/* two longs for us */
 	x = sbrk(n);
 	if((int)x == -1)
 		return nil;
@@ -56,7 +56,7 @@
 static int
 sbrkmerge(void *x, void *y)
 {
-	long *lx, *ly;
+	ulong *lx, *ly;
 
 	lx = x;
 	if(lx[-1] != 0xDeadBeef)