Revert "cmake: Get XKB information directly from PkgConfig"

This reverts commit 3c97cecdb0.

It seems to break on the CI and I don't understand why.

CMakeLists.txt

@@ -185,7 +185,7 @@ if (Wayland_Egl_FOUND)
     set(HAVE_WAYLAND_EGL TRUE)
 endif()
 
-pkg_check_modules(XKB IMPORTED_TARGET xkbcommon)
+find_package(XKB 0.7.0)
 set_package_properties(XKB PROPERTIES
     TYPE REQUIRED
     PURPOSE "Required for building KWin with Wayland support"
@@ -357,6 +357,8 @@ if (KWIN_BUILD_XRENDER_COMPOSITING)
     set(KWIN_HAVE_XRENDER_COMPOSITING 1)
 endif()
 
+include_directories(${XKB_INCLUDE_DIR})
+
 set(HAVE_EPOXY_GLX ${epoxy_HAS_GLX})
 
 # for kwin internal things

autotests/CMakeLists.txt

@@ -368,7 +368,7 @@ target_link_libraries(testXkb
     Plasma::KWaylandServer
     KF5::WindowSystem
 
-    PkgConfig::XKB
+    XKB::XKB
 )
 add_test(NAME kwin-testXkb COMMAND testXkb)
 ecm_mark_as_test(testXkb)

cmake/modules/FindXKB.cmake

@@ -0,0 +1,89 @@
+#.rst:
+# FindXKB
+# -------
+#
+# Try to find xkbcommon on a Unix system
+# If found, this will define the following variables:
+#
+#   ``XKB_FOUND``
+#     True if XKB is available
+#   ``XKB_LIBRARIES``
+#     Link these to use XKB
+#   ``XKB_INCLUDE_DIRS``
+#     Include directory for XKB
+#   ``XKB_DEFINITIONS``
+#     Compiler flags for using XKB
+#
+# Additionally, the following imported targets will be defined:
+#
+#   ``XKB::XKB``
+#     The XKB library
+
+#=============================================================================
+# SPDX-FileCopyrightText: 2014 Martin Gräßlin <mgraesslin@kde.org>
+#
+# SPDX-License-Identifier: BSD-3-Clause
+#=============================================================================
+
+if(CMAKE_VERSION VERSION_LESS 2.8.12)
+    message(FATAL_ERROR "CMake 2.8.12 is required by FindXKB.cmake")
+endif()
+if(CMAKE_MINIMUM_REQUIRED_VERSION VERSION_LESS 2.8.12)
+    message(AUTHOR_WARNING "Your project should require at least CMake 2.8.12 to use FindXKB.cmake")
+endif()
+
+if(NOT WIN32)
+    # Use pkg-config to get the directories and then use these values
+    # in the FIND_PATH() and FIND_LIBRARY() calls
+    find_package(PkgConfig)
+    pkg_check_modules(PKG_XKB QUIET xkbcommon)
+
+    set(XKB_DEFINITIONS ${PKG_XKB_CFLAGS_OTHER})
+
+    find_path(XKB_INCLUDE_DIR
+        NAMES
+            xkbcommon/xkbcommon.h
+        HINTS
+            ${PKG_XKB_INCLUDE_DIRS}
+    )
+    find_library(XKB_LIBRARY
+        NAMES
+            xkbcommon
+        HINTS
+            ${PKG_XKB_LIBRARY_DIRS}
+    )
+
+    set(XKB_LIBRARIES ${XKB_LIBRARY})
+    set(XKB_INCLUDE_DIRS ${XKB_INCLUDE_DIR})
+    set(XKB_VERSION ${PKG_XKB_VERSION})
+
+    include(FindPackageHandleStandardArgs)
+    find_package_handle_standard_args(XKB
+        FOUND_VAR
+            XKB_FOUND
+        REQUIRED_VARS
+            XKB_LIBRARY
+            XKB_INCLUDE_DIR
+        VERSION_VAR
+            XKB_VERSION
+    )
+
+    if(XKB_FOUND AND NOT TARGET XKB::XKB)
+        add_library(XKB::XKB UNKNOWN IMPORTED)
+        set_target_properties(XKB::XKB PROPERTIES
+            IMPORTED_LOCATION "${XKB_LIBRARY}"
+            INTERFACE_COMPILE_OPTIONS "${XKB_DEFINITIONS}"
+            INTERFACE_INCLUDE_DIRECTORIES "${XKB_INCLUDE_DIR}"
+        )
+    endif()
+
+else()
+    message(STATUS "FindXKB.cmake cannot find XKB on Windows systems.")
+    set(XKB_FOUND FALSE)
+endif()
+
+include(FeatureSummary)
+set_package_properties(XKB PROPERTIES
+    URL "https://xkbcommon.org"
+    DESCRIPTION "XKB API common to servers and clients."
+)

src/CMakeLists.txt

@@ -230,7 +230,7 @@ target_link_libraries(kwin
 
     Libinput::Libinput
     UDev::UDev
-    PkgConfig::XKB
+    XKB::XKB
     epoxy::epoxy
 
     ${CMAKE_THREAD_LIBS_INIT}