Modernize CMake install

The lib still doesn't produce a CMake config file i.e.
https://gitlab.kitware.com/cmake/community/-/wikis/doc/tutorials/How-to-create-a-ProjectConfig.cmake-file.
This change creates one and lets KenLM interact with modern CMake
projects without a ton of Findkenlm.cmake cruft.

Other improvements include:
- Remove duplicative linking of `${Boost_LIBRARIES}` and instead link
  to kenlm_util once then transitively to other targets
- Do the same for Threads::Threads
- Both of the above libraries are handled for transitive linking via
  CMake's `find_dependency(...)` in the genreated `kenlmConfig.cmake`
- Wrap libraries in `BUILD_INTERFACE` so that libraries that find KenLM
  don't transitively compile with lib and include paths that are the
  same as the machines KenLM was compiled in

CMakeLists.txt

@@ -111,3 +111,32 @@ if(ENABLE_PYTHON)
   add_subdirectory(python)
 endif()
 
+# Asset installation
+install(
+  TARGETS kenlm kenlm_util
+  EXPORT kenlmTargets
+  RUNTIME DESTINATION bin
+  LIBRARY DESTINATION lib
+  ARCHIVE DESTINATION lib
+)
+
+install(EXPORT kenlmTargets
+  FILE kenlmTargets.cmake
+  NAMESPACE kenlm::
+  DESTINATION share/kenlm/cmake
+)
+
+# Config
+include(CMakePackageConfigHelpers)
+# generate the config file that is includes the exports
+configure_package_config_file(${PROJECT_SOURCE_DIR}/cmake/kenlmConfig.cmake.in
+  "${CMAKE_CURRENT_BINARY_DIR}/kenlmConfig.cmake"
+  INSTALL_DESTINATION share/kenlm/cmake
+  NO_SET_AND_CHECK_MACRO
+  NO_CHECK_REQUIRED_COMPONENTS_MACRO
+  )
+# install the configuration file
+install(FILES
+  ${CMAKE_CURRENT_BINARY_DIR}/kenlmConfig.cmake
+  DESTINATION share/kenlm/cmake
+  )

cmake/kenlmConfig.cmake.in

@@ -0,0 +1,11 @@
+@PACKAGE_INIT@
+
+include(CMakeFindDependencyMacro)
+
+find_dependency(Boost)
+find_dependency(Threads)
+find_dependency(ZLIB)
+find_dependency(BZip2)
+find_dependency(LibLZMA)
+
+include("${CMAKE_CURRENT_LIST_DIR}/kenlmTargets.cmake")

lm/CMakeLists.txt

@@ -32,17 +32,11 @@ add_subdirectory(common)
 
 add_library(kenlm ${KENLM_LM_SOURCE} ${KENLM_LM_COMMON_SOURCE})
 set_target_properties(kenlm PROPERTIES POSITION_INDEPENDENT_CODE ON)
-target_link_libraries(kenlm PUBLIC kenlm_util ${Boost_LIBRARIES} Threads::Threads)
+target_link_libraries(kenlm PUBLIC kenlm_util Threads::Threads)
 
 set(KENLM_MAX_ORDER 6 CACHE STRING "Maximum supported ngram order")
 target_compile_definitions(kenlm PUBLIC -DKENLM_MAX_ORDER=${KENLM_MAX_ORDER})
 
-install(TARGETS kenlm
-  RUNTIME DESTINATION bin
-  LIBRARY DESTINATION lib
-  ARCHIVE DESTINATION lib
-)
-
 # This directory has children that need to be processed
 add_subdirectory(builder)
 add_subdirectory(filter)
@@ -54,9 +48,9 @@ set(EXE_LIST
   fragment
   build_binary
   kenlm_benchmark
-)
+  )
 
-set(LM_LIBS kenlm kenlm_util ${Boost_LIBRARIES} Threads::Threads)
+set(LM_LIBS kenlm kenlm_util Threads::Threads)
 
 AddExes(EXES ${EXE_LIST}
         LIBRARIES ${LM_LIBS})

lm/builder/CMakeLists.txt

@@ -28,12 +28,12 @@ set(KENLM_BUILDER_SOURCE
 #
 add_library(kenlm_builder ${KENLM_BUILDER_SOURCE})
 
-target_link_libraries(kenlm_builder PUBLIC kenlm kenlm_util ${Boost_LIBRARIES} Threads::Threads)
+target_link_libraries(kenlm_builder PUBLIC kenlm kenlm_util Threads::Threads)
 
 AddExes(EXES lmplz
-        LIBRARIES kenlm_builder kenlm kenlm_util ${Boost_LIBRARIES} Threads::Threads)
+        LIBRARIES kenlm_builder kenlm kenlm_util Threads::Threads)
 AddExes(EXES count_ngrams
-        LIBRARIES kenlm_builder kenlm kenlm_util ${Boost_LIBRARIES} Threads::Threads)
+        LIBRARIES kenlm_builder kenlm kenlm_util Threads::Threads)
 
 if(BUILD_TESTING)
 
@@ -44,5 +44,5 @@ if(BUILD_TESTING)
   )
 
   AddTests(TESTS ${KENLM_BOOST_TESTS_LIST}
-           LIBRARIES kenlm_builder kenlm kenlm_util ${Boost_LIBRARIES} Threads::Threads)
+           LIBRARIES kenlm_builder kenlm kenlm_util Threads::Threads)
 endif()

util/CMakeLists.txt

@@ -80,18 +80,15 @@ endif()
 # Group these objects together for later use.
 add_library(kenlm_util ${KENLM_UTIL_DOUBLECONVERSION_SOURCE} ${KENLM_UTIL_STREAM_SOURCE} ${KENLM_UTIL_SOURCE})
 set_target_properties(kenlm_util PROPERTIES POSITION_INDEPENDENT_CODE ON)
-target_link_libraries(kenlm_util PUBLIC ${Boost_LIBRARIES} ${READ_COMPRESSED_LIBS} Threads::Threads ${RT})
-
-install(TARGETS kenlm_util
-  RUNTIME DESTINATION bin
-  LIBRARY DESTINATION lib
-  ARCHIVE DESTINATION lib
-)
-
+target_link_libraries(kenlm_util PUBLIC
+  "$<BUILD_INTERFACE:${Boost_LIBRARIES}>"
+  "$<BUILD_INTERFACE:${READ_COMPRESSED_LIBS}>"
+  $<BUILD_INTERFACE:Threads::Threads>
+  $<BUILD_INTERFACE:${RT}>)
 
 if (NOT WIN32)
 AddExes(EXES probing_hash_table_benchmark
-        LIBRARIES kenlm_util ${Boost_LIBRARIES} Threads::Threads)
+        LIBRARIES kenlm_util Threads::Threads)
 endif()
 
 # Only compile and run unit tests if tests should be run
@@ -111,10 +108,10 @@ if(BUILD_TESTING)
   )
 
   AddTests(TESTS ${KENLM_BOOST_TESTS_LIST}
-           LIBRARIES kenlm_util ${Boost_LIBRARIES} Threads::Threads)
+           LIBRARIES kenlm_util Threads::Threads)
 
   # file_piece_test requires an extra command line parameter
   KenLMAddTest(TEST file_piece_test
-               LIBRARIES kenlm_util ${Boost_LIBRARIES} Threads::Threads
+               LIBRARIES kenlm_util Threads::Threads
                TEST_ARGS ${CMAKE_CURRENT_SOURCE_DIR}/file_piece.cc)
 endif()