Fix signed/unsigned warnings.
diff --git a/engines/e_cswift.c b/engines/e_cswift.c
index 2017e48..d5f1d4e 100644
--- a/engines/e_cswift.c
+++ b/engines/e_cswift.c
@@ -1062,7 +1062,7 @@
 	/* limitation of cswift with values not a multiple of 32                */
 	/************************************************************************/
 
-	while(num >= sizeof(buf32))
+	while(num >= (int)sizeof(buf32))
 	{
 		largenum.value = buf;
 		largenum.nbytes = sizeof(buf32);