[io] Fix the following warning. src/io/socket_unix.c:255: warning: ISO C90 forbids mixed declarations and code
[io] Fix the following warning.
src/io/socket_unix.c:255: warning: ISO C90 forbids mixed declarations and code

git-svn-id: 6e74a02f85675cec270f5d931b0f6998666294a3@37711 d31e2699-5ff4-0310-a27c-f18f2fbe73fe

ashgti/parrot,ashgti/parrot,ashgti/parrot,ashgti/parrot,ashgti/parrot,ashgti/parrot,ashgti/parrot