Installed versions of mesalib and libxcb don't fit.

[donald]

#927 (merged) update the package measlib from 18.1.6 to 18.2.1. #926 (umerged) attempts to update the package libxcb from 1.12 to 1.13.

The installed version of libEGL.so.1.so from the package mesalib 18.2.1 uses symbols, which are provided by version libxcb-dri3.so.0 from libxcb 1.13, which are not available in libxcb-dri3.so.0 from libxcb 1.12:

buczek@theinternet:~/git/bee-files (master)$ pip3 install --user PyQt5
[...]
buczek@theinternet:~/git/bee-files (master)$ python3
[...]
>>> import PyQt5.QtWebEngineWidgets
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ImportError: /usr/lib/libEGL.so.1: undefined symbol: xcb_dri3_get_supported_modifiers

Additionally, the package mesalib 18.2.1 can't be rebuilt, which may hint that it was built on a system with libxcb 1.13 already installed:

sudo ./mesalib.be0
  CC       wsi/wsi_common_x11.lo
/scratch/local/bee-root/mesalib/mesalib-18.2.1-1/source/src/vulkan/wsi/wsi_common_x11.c: In function 'x11_manage_fifo_queues':
/scratch/local/bee-root/mesalib/mesalib-18.2.1-1/source/src/vulkan/wsi/wsi_common_x11.c:1007:14: warning: 'image_index' may be used uninitialized in this function [-Wmaybe-uninitialized]
       result = x11_present_to_x11(chain, image_index, target_msc);
       ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  CC       wsi/wsi_common_display.lo
/scratch/local/bee-root/mesalib/mesalib-18.2.1-1/source/src/vulkan/wsi/wsi_common_display.c: In function 'wsi_acquire_xlib_display':
/scratch/local/bee-root/mesalib/mesalib-18.2.1-1/source/src/vulkan/wsi/wsi_common_display.c:2307:4: error: unknown type name 'xcb_randr_lease_t'; did you mean 'xcb_randr_mode_t'?
    xcb_randr_lease_t lease = xcb_generate_id(connection);
    ^~~~~~~~~~~~~~~~~
    xcb_randr_mode_t
/scratch/local/bee-root/mesalib/mesalib-18.2.1-1/source/src/vulkan/wsi/wsi_common_display.c:2308:4: error: unknown type name 'xcb_randr_create_lease_cookie_t'; did you mean 'xcb_randr_create_mode_cookie_t'?
    xcb_randr_create_lease_cookie_t cl_c =
[...]

Updating libxcb to 1.13 fixes the immediate problem. However, after the update, problems with the mouse wheel and keys becoming unresponsive during scrolling with the mouse wheel, were noted. So this needs more testing.

[pmenzel]

I reported the libxcb regression upstream.

[pmenzel]

This was fixed by #936.