libxcb-sync1-dbg binary package in Ubuntu Trusty amd64

 This package contains the debugging symbols associated with
 libxcb-sync, the sync extension for the X C Binding. gdb will
 automatically use these symbols when debugging libxcb-sync.
 .
 The XCB library provides an interface to the X Window System protocol,
 designed to replace the Xlib interface. XCB provides several advantages over
 Xlib:
 .
  * Size: small library and lower memory footprint
  * Latency hiding: batch several requests and wait for the replies later
  * Direct protocol access: one-to-one mapping between interface and protocol
  * Thread support: access XCB from multiple threads, with no explicit locking
  * Easy creation of new extensions: automatically generates interface from
    machine-parsable protocol descriptions

Source package