added a dummy implementation of GetLastOSError

git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@24652 3ad0048d-3df7-0310-abae-a5850022a9f2
disabled sockets unit, because it doesn't build ATM

git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@24653 3ad0048d-3df7-0310-abae-a5850022a9f2