Add logid service & install target

src/logid/CMakeLists.txt

@@ -1,4 +1,4 @@
-cmake_minimum_required(VERSION 3.14)
+cmake_minimum_required(VERSION 3.10)
 project(logid)
 
 set(CMAKE_CXX_STANDARD 14)
@@ -25,8 +25,7 @@ add_executable(logid
 set_target_properties(logid PROPERTIES RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR})
 
 pkg_check_modules(PC_EVDEV libevdev)
-pkg_check_modules(libhidpp REQUIRED)
-pkg_check_modules(libconfig++ REQUIRED)
+pkg_check_modules(SYSTEMD "systemd")
 
 find_path(HIDPP_INCLUDE_DIR hidpp)
 find_library(HIDPP_LIBRARY libhidpp.so)
@@ -39,3 +38,20 @@ find_library(EVDEV_LIBRARY
 include_directories(${HIDPP_INCLUDE_DIR}/hidpp ${EVDEV_INCLUDE_DIR})
 
 target_link_libraries(logid ${CMAKE_THREAD_LIBS_INIT} ${EVDEV_LIBRARY} config++ ${HIDPP_LIBRARY})
+
+install(TARGETS logid DESTINATION bin)
+
+if (SYSTEMD_FOUND AND "${SYSTEMD_SERVICES_INSTALL_DIR}" STREQUAL "")
+    execute_process(COMMAND ${PKG_CONFIG_EXECUTABLE}
+        --variable=systemdsystemunitdir systemd
+        OUTPUT_VARIABLE SYSTEMD_SERVICES_INSTALL_DIR)
+    string(REGEX REPLACE "[ \t\n]+" "" SYSTEMD_SERVICES_INSTALL_DIR
+           "${SYSTEMD_SERVICES_INSTALL_DIR}")
+    configure_file(logid.service.cmake ${CMAKE_BINARY_DIR}/logid.service)
+    message(STATUS "systemd units will be installed at ${SYSTEMD_SERVICES_INSTALL_DIR}")
+    install(FILES ${CMAKE_BINARY_DIR}/logid.service
+            DESTINATION ${SYSTEMD_SERVICES_INSTALL_DIR}
+            COMPONENT cp)
+elseif(NOT SYSTEMD_FOUND AND SYSTEMD_SERVICES_INSTALL_DIR)
+    message(FATAL_ERROR "systemd is not found w/ pkg-config but SYSTEMD_SERVICES_INSTALL_DIR is defined.")
+endif()