diff -urNp star-1.5.1-orig/star/buffer.c star-1.5.1/star/buffer.c
--- star-1.5.1-orig/star/buffer.c	2009-07-13 21:05:02.000000000 +0200
+++ star-1.5.1/star/buffer.c	2011-01-04 13:50:25.452138625 +0100
@@ -799,7 +799,7 @@ initbuf(nblocks)
 
 		bigptr = bigbuf = ___malloc((size_t) bufsize+10+pagesize,
 								"buffer");
-		bigptr = bigbuf = (char *)roundup((Intptr_t)bigptr, pagesize);
+		bigptr = bigbuf = (char *)roundup((UIntptr_t)bigptr, pagesize);
 		fillbytes(bigbuf, bufsize, '\0');
 		fillbytes(&bigbuf[bufsize], 10, 'U');