root# cd buildroot
root# make
>>> host-libxcb 1.12 Building
PATH="/root/buildroot/output/host/bin:/root/buildroot/output/host/sbin:/root/buildroot/output/host/usr/bin:/root/buildroot/output/host/usr/sbin:/bin:/usr/bin:/sbin:/usr/sbin:/usr/local/bin:/root/my-applications/bin:/usr/games" PKG_CONFIG="/root/buildroot/output/host/usr/bin/pkg-config" PKG_CONFIG_SYSROOT_DIR="/" PKG_CONFIG_ALLOW_SYSTEM_CFLAGS=1 PKG_CONFIG_ALLOW_SYSTEM_LIBS=1 PKG_CONFIG_LIBDIR="/root/buildroot/output/host/usr/lib/pkgconfig:/root/buildroot/output/host/usr/share/pkgconfig"  /usr/bin/make -j3  -C /root/buildroot/output/build/host-libxcb-1.12/
make[1]: Entering directory `/root/buildroot/output/build/host-libxcb-1.12'
Making all in src
make[2]: Entering directory `/root/buildroot/output/build/host-libxcb-1.12/src'
make[2]: warning: -jN forced in submake: disabling jobserver mode.
  GEN      xproto.c
  GEN      bigreq.c
  GEN      xc_misc.c

Failed to load the xcbgen Python package!
Make sure that xcb/proto installed it on your Python path.
If not, you will need to create a .pth file or define $PYTHONPATH
to extend the path.
Refer to the README file in xcb/proto for more info.

Traceback (most recent call last):
  File "./c_client.py", line 3294, in <module>
    from xcbgen.state import Module
  File "/root/buildroot/output/host/usr/lib/python2.7/site-packages/xcbgen/state.py", line 5, in <module>
    from xml.etree.cElementTree import parse
  File "/root/buildroot/output/host/usr/lib/python2.7/xml/etree/cElementTree.py", line 3, in <module>
    from _elementtree import *
ImportError: /root/buildroot/output/host/usr/lib/python2.7/lib-dynload/_elementtree.so: undefined symbol: PyUnicodeUCS2_FromFormat
make[2]: *** [bigreq.c] Error 1
make[2]: *** Waiting for unfinished jobs....

Failed to load the xcbgen Python package!
Make sure that xcb/proto installed it on your Python path.
If not, you will need to create a .pth file or define $PYTHONPATH
to extend the path.
Refer to the README file in xcb/proto for more info.

Traceback (most recent call last):
  File "./c_client.py", line 3294, in <module>
    from xcbgen.state import Module
  File "/root/buildroot/output/host/usr/lib/python2.7/site-packages/xcbgen/state.py", line 5, in <module>
    from xml.etree.cElementTree import parse
  File "/root/buildroot/output/host/usr/lib/python2.7/xml/etree/cElementTree.py", line 3, in <module>
    from _elementtree import *
ImportError: /root/buildroot/output/host/usr/lib/python2.7/lib-dynload/_elementtree.so: undefined symbol: PyUnicodeUCS2_FromFormat
make[2]: *** [xc_misc.c] Error 1

Failed to load the xcbgen Python package!
Make sure that xcb/proto installed it on your Python path.
If not, you will need to create a .pth file or define $PYTHONPATH
to extend the path.
Refer to the README file in xcb/proto for more info.

Traceback (most recent call last):
  File "./c_client.py", line 3294, in <module>
    from xcbgen.state import Module
  File "/root/buildroot/output/host/usr/lib/python2.7/site-packages/xcbgen/state.py", line 5, in <module>
    from xml.etree.cElementTree import parse
  File "/root/buildroot/output/host/usr/lib/python2.7/xml/etree/cElementTree.py", line 3, in <module>
    from _elementtree import *
ImportError: /root/buildroot/output/host/usr/lib/python2.7/lib-dynload/_elementtree.so: undefined symbol: PyUnicodeUCS2_FromFormat
make[2]: *** [xproto.c] Error 1
make[2]: Leaving directory `/root/buildroot/output/build/host-libxcb-1.12/src'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/root/buildroot/output/build/host-libxcb-1.12'
make: *** [/root/buildroot/output/build/host-libxcb-1.12/.stamp_built] Error 2
root#

Soory, it is my .config file:
http://code.bulix.org/bsvjtr-115121

Created attachment 6891 [details]
my .config file

It is my config file

I have successfully built the following defconfig (based on yours):

BR2_TOOLCHAIN_EXTERNAL=y
BR2_TARGET_GENERIC_HOSTNAME="skamilinux"
BR2_TARGET_GENERIC_ISSUE="Welcome to SkamiLinux !"
BR2_ROOTFS_DEVICE_CREATION_DYNAMIC_EUDEV=y
BR2_ENABLE_LOCALE_WHITELIST="C en_US hu hu_HU"
BR2_PACKAGE_GETTEXT=y
BR2_PACKAGE_LIBERATION=y
BR2_PACKAGE_XORG7=y
BR2_PACKAGE_XSERVER_XORG_SERVER=y
BR2_PACKAGE_XSERVER_XORG_SERVER_XVFB=y
BR2_PACKAGE_LIBDRM=y
BR2_PACKAGE_LIBDRM_INTEL=y
BR2_PACKAGE_LIBDRM_RADEON=y
BR2_PACKAGE_LIBDRM_AMDGPU=y
BR2_PACKAGE_LIBDRM_NOUVEAU=y
BR2_PACKAGE_LIBDRM_VMWGFX=y
BR2_PACKAGE_MTDEV=y
BR2_PACKAGE_LIBEVDEV=y
BR2_PACKAGE_LIBFFI=y
BR2_PACKAGE_NCURSES=y
BR2_PACKAGE_NCURSES_WCHAR=y
BR2_PACKAGE_PCRE=y
BR2_PACKAGE_PCRE_UCP=y
BR2_PACKAGE_GOOGLEFONTDIRECTORY=y
BR2_PACKAGE_UTIL_LINUX_LIBMOUNT=y
BR2_TARGET_ROOTFS_CPIO=y
BR2_TARGET_ROOTFS_CPIO_GZIP=y
BR2_TARGET_ROOTFS_SQUASHFS=y
# BR2_TARGET_ROOTFS_TAR is not set

So I believe your error is most likely due to a partial build.

Can you double check that you still get this error after doing "make clean all" ? Thanks.

Created attachment 6896 [details]
xproto_xproto-7.0.31 error

Thank you for your job.

I made defconfig based on your config.
Made make clean all and than make.

The new attached file xproto_xproto-7.0.31 error.

So there is in fact no build issue with libxcb, correct? If that's the case, then it would be better to close this bug, and re-open a new one so that things are clear.

Are you starting the build with just a plain "make", or using "make -j<somenumber>" ?

Yes, close this and a new open.

This config was copied from here so there is no cpu selection.
I use only simply make.

What should i do and how ?
Select the resolved option?

Sorry for lama questions....
:-(

One time i have deleted this directory and building will continue and finally libxcb will be the problem again.