suppres Python 2.3 warning


git-svn-id: svn://svn.code.sf.net/p/fonttools/code/trunk@381 4cde692c-a291-49d1-8350-778aa11640f8
diff --git a/Lib/fontTools/ttLib/sfnt.py b/Lib/fontTools/ttLib/sfnt.py
index 93f70b6..bd5fe7a 100644
--- a/Lib/fontTools/ttLib/sfnt.py
+++ b/Lib/fontTools/ttLib/sfnt.py
@@ -150,7 +150,8 @@
 		checksums[-1] = calcChecksum(directory)
 		checksum = Numeric.add.reduce(checksums)
 		# BiboAfba!
-		checksumadjustment = Numeric.array(0xb1b0afba) - checksum
+		checksumadjustment = Numeric.array(0xb1b0afbaL - 0x100000000L,
+				Numeric.Int32) - checksum
 		# write the checksum to the file
 		self.file.seek(self.tables['head'].offset + 8)
 		self.file.write(struct.pack(">l", checksumadjustment))