Bug#1084784: kf6-kwindowsystem FTBFS with the nocheck build profile: xcb-icccm not found

[Helmut Grohne <helmut@subdivi.de>]

Source: kf6-kwindowsystem
Version: 6.6.0-1
Tags: ftbfs trixie sid
Justification: nocheck ftbfs is rc since trixie

kf6-kwindowsystem fails to build from source when enabling the nocheck
build profile. The relevant excerpt from the log is:

| -- Found XCB_XCB: /usr/lib/powerpc64le-linux-gnu/libxcb.so (found version "1.17.0")
| -- Could NOT find XCB_ICCCM (missing: XCB_ICCCM_LIBRARY XCB_ICCCM_INCLUDE_DIR) (found version "")
| -- Found XCB_KEYSYMS: /usr/lib/powerpc64le-linux-gnu/libxcb-keysyms.so (found version "0.4.0")
| -- Found XCB_RES: /usr/lib/powerpc64le-linux-gnu/libxcb-res.so (found version "1.17.0")
| CMake Error at /usr/share/cmake-3.30/Modules/FindPackageHandleStandardArgs.cmake:233 (message):
|   Could NOT find XCB (missing: ICCCM) (found version "1.17.0")
| Call Stack (most recent call first):
|   /usr/share/cmake-3.30/Modules/FindPackageHandleStandardArgs.cmake:603 (_FPHSA_FAILURE_MESSAGE)
|   /usr/share/ECM/find-modules/FindXCB.cmake:154 (find_package_handle_standard_args)
|   CMakeLists.txt:62 (find_package)
| 
| 
| -- Configuring incomplete, errors occurred!
|         cd obj-powerpc64le-linux-gnu && tail -v -n \+0 CMakeCache.txt

I'm not sure why libxcb-icccm-dev is annotated <!nocheck> in
debian/control, but it probably should not be and removing the
annotation is a quick way to resolve this bug.

Helmut