scons: Enable -Wextra by default

Make best use of the compiler, and enable -Wextra as well as
-Wall. There are a few issues that had to be resolved, but they are
all trivial.

1 files changed, 1 insertions, 1 deletions

diff --git a/src/dev/net/ethertap.cc b/src/dev/net/ethertap.cc
index e8d6a363c..e8ece152e 100644
--- a/src/dev/net/ethertap.cc
+++ b/src/dev/net/ethertap.cc
@@ -241,8 +241,8 @@ EtherTap::process(int revent)
         packet->length = data_len;
         memcpy(packet->data, data, data_len);
 
+        assert(buffer_offset >= data_len + sizeof(uint32_t));
         buffer_offset -= data_len + sizeof(uint32_t);
-        assert(buffer_offset >= 0);
         if (buffer_offset > 0) {
             memmove(buffer, data + data_len, buffer_offset);
             data_len = ntohl(*(uint32_t *)buffer);