Socket: Scale send buffers to avoid blocking during refill.

The buffer are doubled before writing data to the socket. Later, they
are brought back to original size.

git-svn-id: svn://svn.code.sf.net/p/dmtcp/code/trunk@2621 ba6dc0ae-232f-0410-883f-9ebac64fc565
Socket: Fix definition of incoming/outgoing during restart.

TCP_Connect -> outgoing.
TCP_Accept  -> incoming.

git-svn-id: svn://svn.code.sf.net/p/dmtcp/code/trunk@2622 ba6dc0ae-232f-0410-883f-9ebac64fc565
Socket: Minor cleanup.

git-svn-id: svn://svn.code.sf.net/p/dmtcp/code/trunk@2623 ba6dc0ae-232f-0410-883f-9ebac64fc565
Added Util::changeFd().

git-svn-id: svn://svn.code.sf.net/p/dmtcp/code/trunk@2624 ba6dc0ae-232f-0410-883f-9ebac64fc565
Cosmetic changes to protectedfds.h.

git-svn-id: svn://svn.code.sf.net/p/dmtcp/code/trunk@2625 ba6dc0ae-232f-0410-883f-9ebac64fc565
Remove include/*.h from .gitignore.

git-svn-id: svn://svn.code.sf.net/p/dmtcp/code/trunk@2626 ba6dc0ae-232f-0410-883f-9ebac64fc565
Socket: Added support for Unix Domain Sockets

Also added support for proper restoration of IPv6 sockets. It is
currently disabled, and will be enabled after the next tag.

git-svn-id: svn://svn.code.sf.net/p/dmtcp/code/trunk@2627 ba6dc0ae-232f-0410-883f-9ebac64fc565