Clean up struct NestedClientPrivate.
Add missing 'const' qualifier to xcb_query_extension_reply_t variables.
Fix first argument of xcb_image_put() call.
Fix mistyping in xcb_get_modifier_mapping_* related stuff.
Fix xcb_keysym_t to KeySym casting in assignment.
Update #include's.
Include XCB-related stuff in configure.ac and src/Makefile.am.
Replace xlibclient.c with xcbclient.c in src/Makefile.am.