After bisection, the first libxcb that fails to build is
libxcb-1f6cd9f1fcd3c07d323b678292c9cb00ae1f7504, Only #include directly referenced module header files, by Keith Packard, 2014-03-22. 
Make shows the following error:
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Making all in src
make[1]: Entering directory `~/src/xorg/libxcb-1f6cd9f1fcd3c07d323b678292c9cb00ae1f7504/src'
  GEN      xproto.c
  GEN      bigreq.c
Traceback (most recent call last):
  File "./c_client.py", line 3031, in <module>
    module.generate()
  File "/usr/lib/python2.7/dist-packages/xcbgen/state.py", line 100, in generate
    self.open()
  File "./c_client.py", line 193, in c_open
    for (n, h) in self.direct_imports:
AttributeError: 'Module' object has no attribute 'direct_imports'
Error in sys.excepthook:
Traceback (most recent call last):
  File "/usr/lib/python2.7/dist-packages/apport_python_hook.py", line 64, in apport_excepthook
    from apport.fileutils import likely_packaged, get_recent_crashes
  File "/usr/lib/python2.7/dist-packages/apport/__init__.py", line 5, in <module>
    from apport.report import Report
  File "/usr/lib/python2.7/dist-packages/apport/report.py", line 30, in <module>
    import apport.fileutils
  File "/usr/lib/python2.7/dist-packages/apport/fileutils.py", line 23, in <module>
    from apport.packaging_impl import impl as packaging
  File "/usr/lib/python2.7/dist-packages/apport/packaging_impl.py", line 20, in <module>
    import apt
  File "/usr/lib/python2.7/dist-packages/apt/__init__.py", line 34, in <module>
    apt_pkg.init_config()
SystemError: E:Opening configuration file /etc/apt/apt.conf.d/triggers - ifstream::ifstream (13: Permission denied)

Original exception was:
Traceback (most recent call last):
  File "./c_client.py", line 3031, in <module>
    module.generate()
  File "/usr/lib/python2.7/dist-packages/xcbgen/state.py", line 100, in generate
    self.open()
  File "./c_client.py", line 193, in c_open
    for (n, h) in self.direct_imports:
AttributeError: 'Module' object has no attribute 'direct_imports'
make[1]: *** [bigreq.c] Error 1
make[1]: Leaving directory `~/src/xorg/libxcb-1f6cd9f1fcd3c07d323b678292c9cb00ae1f7504/src'
make: *** [all-recursive] Error 1
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