update engine: 32- and 64-bit compile

Review URL: http://codereview.chromium.org/1599029
diff --git a/decompressing_file_writer_unittest.cc b/decompressing_file_writer_unittest.cc
index 1d689e7..c1666db 100644
--- a/decompressing_file_writer_unittest.cc
+++ b/decompressing_file_writer_unittest.cc
@@ -75,7 +75,8 @@
   uncompressed_file.Close();
 
   // compress the file
-  system((string("cat ") + kPath + " | gzip > " + kPathgz).c_str());
+  EXPECT_EQ(0,
+            system((string("cat ") + kPath + " | gzip > " + kPathgz).c_str()));
 
   // Now read the compressed file and put it into a DecompressingFileWriter
   MockFileWriter mock_file_writer;