Use upstream FindLibinput

It exists since 3.14

cmake/modules/FindLibinput.cmake

-#.rst:
-# FindLibinput
-# -------
-#
-# Try to find libinput on a Unix system.
-#
-# This will define the following variables:
-#
-# ``Libinput_FOUND``
-#     True if (the requested version of) libinput is available
-# ``Libinput_VERSION``
-#     The version of libinput
-# ``Libinput_LIBRARIES``
-#     This can be passed to target_link_libraries() instead of the ``Libinput::Libinput``
-#     target
-# ``Libinput_INCLUDE_DIRS``
-#     This should be passed to target_include_directories() if the target is not
-#     used for linking
-# ``Libinput_DEFINITIONS``
-#     This should be passed to target_compile_options() if the target is not
-#     used for linking
-#
-# If ``Libinput_FOUND`` is TRUE, it will also define the following imported target:
-#
-# ``Libinput::Libinput``
-#     The libinput library
-#
-# In general we recommend using the imported target, as it is easier to use.
-# Bear in mind, however, that if the target is in the link interface of an
-# exported library, it must be made available by the package config file.
-
-#=============================================================================
-# SPDX-FileCopyrightText: 2014 Alex Merry <alex.merry@kde.org>
-# 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 FindLibinput.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 FindLibinput.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_Libinput QUIET libinput)
-
-    set(Libinput_DEFINITIONS ${PKG_Libinput_CFLAGS_OTHER})
-    set(Libinput_VERSION ${PKG_Libinput_VERSION})
-
-    find_path(Libinput_INCLUDE_DIR
-        NAMES
-            libinput.h
-        HINTS
-            ${PKG_Libinput_INCLUDE_DIRS}
-    )
-    find_library(Libinput_LIBRARY
-        NAMES
-            input
-        HINTS
-            ${PKG_Libinput_LIBRARY_DIRS}
-    )
-
-    include(FindPackageHandleStandardArgs)
-    find_package_handle_standard_args(Libinput
-        FOUND_VAR
-            Libinput_FOUND
-        REQUIRED_VARS
-            Libinput_LIBRARY
-            Libinput_INCLUDE_DIR
-        VERSION_VAR
-            Libinput_VERSION
-    )
-
-    if(Libinput_FOUND AND NOT TARGET Libinput::Libinput)
-        add_library(Libinput::Libinput UNKNOWN IMPORTED)
-        set_target_properties(Libinput::Libinput PROPERTIES
-            IMPORTED_LOCATION "${Libinput_LIBRARY}"
-            INTERFACE_COMPILE_OPTIONS "${Libinput_DEFINITIONS}"
-            INTERFACE_INCLUDE_DIRECTORIES "${Libinput_INCLUDE_DIR}"
-        )
-    endif()
-
-    mark_as_advanced(Libinput_LIBRARY Libinput_INCLUDE_DIR)
-
-    # compatibility variables
-    set(Libinput_LIBRARIES ${Libinput_LIBRARY})
-    set(Libinput_INCLUDE_DIRS ${Libinput_INCLUDE_DIR})
-    set(Libinput_VERSION_STRING ${Libinput_VERSION})
-
-else()
-    message(STATUS "FindLibinput.cmake cannot find libinput on Windows systems.")
-    set(Libinput_FOUND FALSE)
-endif()
-
-include(FeatureSummary)
-set_package_properties(Libinput PROPERTIES
-    URL "https://www.freedesktop.org/wiki/Software/libinput/"
-    DESCRIPTION "Library to handle input devices in Wayland compositors and to provide a generic X.Org input driver."
-)