[xcb] XCL as drop-in Xlib replacement

[Keith Packard]

Around 23 o'clock on Sep 7, jamey@sharp.ath.cx wrote:

> Judging by my tests, the idea is sound. The only problem arises when
> running the version of the test program that was linked against
> 'new', while using the libraries found in 'old'. This corresponds to
> building an application on a system using XCL, then trying to run
> that application on an Xlib-based system. The reason is pretty clear:

As an easy kludge, we can build a library which stubs out references 
to the underlying libraries.  Now we install two .so files:

	libdep1.so	- stubbed out lower dependencies
	libdep1.so.1	- real library

One additional benefit of this mechanism is that the fake .so could
provide only the truely public parts of the interface.

-keith