[PATCH wayland] introduce new headers wayland-client/server-core.h

[Bill Spitzak]

>>>>> The problem is when you have an extension.xml, and generate
>>>>> extension-client-protocol.h. Then you have some preexisting code
>>>>> including that and relying on it including wayland-client.h and then
>>>>> wayland-client-protocol.h, and if you use something from that it will
>>>>> not build anymore, because wayland-client-core.h doesn't include it.

I think it is acceptable to say that the code has to be fixed in this 
case. It will only happen if they call a function that wayland-client.h 
defines but is not in wayland-client-core.h. You are being much too 
concerned about back compatibility here.

Removing the circular dependency in the header files is probably a good 
idea.

If it really is necessary to not break anything, I would write the 
protocol to a different .h file (best I can think of is to remove 
"-protocol" from the current name), and make back-compatibility headers 
that include this file and also wayland-client.h. Then encourage 
programmers to include the new header file. Code that includes the old 
one will still compile. This will also remove the deprecated functions 
from new programs.