Since BroadcastError() calls BroadcastMountError(), there's no need to
check mount_finished here.

While reconnecting to the NFS server, the socket is -1, because there
is no socket.  Fixes a potential crash (assertion failure).

Necessary for "final" on gcc 4.6.

Generate more detailed error messages.

Eliminate duplicate definition (in input plugin and decoder plugin).

Again, POSIX says strcasecmp is not in string.h.

std::map::emplace() is only available from gcc 4.8 on.

More robust and cancellable.

Make valgrind happy.

Turns out ucol_getSortKey() does not what I thought it does.

Fixes the broken "search" command.

Fixes crash after database update.

Fixes initialization failure.

libsmbclient is not thread-safe nor reentrant.  We must protect all
function calls with a global mutex, unfortunately.

Eliminate class LibUPnP and move the code to ClientInit.cxx.  Its
initialization function can be called multiple times, but
UpnpRegisterClient() is called at most once.

Allow calling UpnpGlobalInit() multiple times.

Each Upnp*Async() call passes a new cookie pointer, and the cookie
passed to UpnpRegisterClient() appears to be ignored.  Using this
interface is a more elegant approach than having one single "handler"
function.

This appears to be the right thing to do when we want anonymous login.