[Xcb] xcb_atom.h with missing c++ facilities

[Barton C Massey]

In message <E45AC350-8DBA-4EA8-97CA-EB54D203DF67 at quirkster.com> you wrote:
> My opinion: these are C libraries  (XCB == "X C Binding") and thus  
> should have no C++ constructs in their source or headers.  It is up  
> to C++ users of XCB to wrap xcb includes in extern "C" { } as needed,  
> as they would do when using any other C library. If it were me, I  
> would remove all #ifdef __cplusplus stuff from xcb-util and other xcb  
> related repository code.

This is also my personal preference, but the general
consensus of the community seems to be otherwise. For now we
do indeed already have the rest of the files wrapped, which
makes it confusing when xcb_atom.h isn't.  I've pushed a
patch.

	Bart