Re: [Libvir] [PATCH] A few more Windows / MinGW fixups

A few fairly miscellaneous fixups for Windows (MinGW) which fix shared library builds and fix error handling for sockets. (1) XDR functions on MinGW come from a library called 'libxdr', not 'librpc'. (2) To build a DLL under MinGW we need to pass the -no-undefined flag to the linker. (3) Socket compatibility header file replaces <winsock2.h> inclusion. This just defines a portable 'socket_errno()' function which returns errno in the normal case, or WSAGetLastError() in the Windows case. (4) Use socket_errno() instead of errno in a few cases (but only when the code can be compiled under Windows, ie. only in the remote client case).