Toolchain.cmake to cross-compile kenlm for Android

Question

I try to make kenlm binaries usable on Android. Kenlm is written in c++ and uses cmake, so I tried to do a toolchain file to crosscompile with cmake.

My toolchain file looks like that :

set(CMAKE_SYSTEM_NAME Android)
set(CMAKE_SYSTEM_VERSION 26)
set(CMAKE_ANDROID_ARCH_ABI arm64-v8a)
set(CMAKE_ANDROID_NDK "/home/marie/Android/Sdk/ndk/16.1.4479499")
set(BZIP2_LIBRARIES "/usr/lib/x86_64-linux-gnu")
set(LIBLZMA_LIBRARY "/usr/lib/x86_64-linux-gnu/liblzma.so")
set(LIBLZMA_LIBRARIES "/lib/x86_64-linux-gnu")
set(LIBLZMA_HAS_AUTO_DECODER TRUE)
set(LIBLZMA_HAS_EASY_ENCODER TRUE)
set(LIBLZMA_HAS_LZMA_PRESET TRUE)
set(ZLIB_LIBRARIES "/home/marie/Android/Sdk/ndk/16.1.4479499/platforms/android-26/arch-arm64/usr/lib")

and the CMakeLists.txt from kenlm

cmake_minimum_required(VERSION 2.6)

# Define a single cmake project
project(kenlm)
option(FORCE_STATIC "Build static executables" OFF)
if (FORCE_STATIC)
  #presumably overkill, is there a better way?
  #http://cmake.3232098.n2.nabble.com/Howto-compile-static-executable-td5580269.html
  set(Boost_USE_STATIC_LIBS ON)
  set_property(GLOBAL PROPERTY LINK_SEARCH_START_STATIC ON)
  set_property(GLOBAL PROPERTY LINK_SEARCH_END_STATIC ON)
  set(BUILD_SHARED_LIBRARIES OFF)
  if (MSVC)
    set(flag_vars
      CMAKE_CXX_FLAGS CMAKE_CXX_FLAGS_DEBUG CMAKE_CXX_FLAGS_RELEASE
      CMAKE_CXX_FLAGS_MINSIZEREL CMAKE_CXX_FLAGS_RELWITHDEBINFO
      CMAKE_C_FLAGS CMAKE_C_FLAGS_DEBUG CMAKE_C_FLAGS_RELEASE
      CMAKE_C_FLAGS_MINSIZEREL CMAKE_C_FLAGS_RELWITHDEBINFO)
      foreach(flag_var ${flag_vars})
        if(${flag_var} MATCHES "/MD")
          string(REGEX REPLACE "/MD" "/MT" ${flag_var} "${${flag_var}}")
        endif(${flag_var} MATCHES "/MD")
      endforeach(flag_var)
  else (MSVC)
    if (NOT CMAKE_C_COMPILER_ID MATCHES ".*Clang")
      set(CMAKE_EXE_LINKER_FLAGS "-static-libgcc -static-libstdc++ -static")
    endif ()
  set(CMAKE_FIND_LIBRARY_SUFFIXES ".a")
  endif ()
  #Annoyingly the exectuables say "File not found" unless these are set
  set(CMAKE_EXE_LINK_DYNAMIC_C_FLAGS)
  set(CMAKE_EXE_LINK_DYNAMIC_CXX_FLAGS)
  set(CMAKE_SHARED_LIBRARY_C_FLAGS)
  set(CMAKE_SHARED_LIBRARY_CXX_FLAGS)
  set(CMAKE_SHARED_LIBRARY_LINK_C_FLAGS)
  set(CMAKE_SHARED_LIBRARY_LINK_CXX_FLAGS)
endif ()

# Compile all executables into bin/
set(EXECUTABLE_OUTPUT_PATH ${PROJECT_BINARY_DIR}/bin)

# Compile all libraries into lib/
set(LIBRARY_OUTPUT_PATH ${PROJECT_BINARY_DIR}/lib)

if (NOT CMAKE_BUILD_TYPE)
  set(CMAKE_BUILD_TYPE Release)
endif()

option(COMPILE_TESTS "Compile tests" OFF)
if (COMPILE_TESTS)
  # Tell cmake that we want unit tests to be compiled
  include(CTest)
  enable_testing()
endif()

# Add our CMake helper functions
include(cmake/KenLMFunctions.cmake)

if(MSVC)
  set(CMAKE_C_FLAGS "${CMAKE_CXX_FLAGS} /w34716")
  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /w34716")
endif()

# And our helper modules
list(APPEND CMAKE_MODULE_PATH ${PROJECT_SOURCE_DIR}/cmake/modules)

# We need boost
find_package(Boost 1.41.0 REQUIRED COMPONENTS
  program_options
  system
  thread
  unit_test_framework
)

# Define where include files live
include_directories(
  ${PROJECT_SOURCE_DIR}
  ${Boost_INCLUDE_DIRS}

)

# Process subdirectories
add_subdirectory(util)
add_subdirectory(lm)

When i try to

cmake -DCMAKE_TOOLCHAIN_FILE="./cmake_toolchain.cmake" ..

I get that

...
  Unable to find the requested Boost libraries.

  Boost version: 1.65.1

  Boost include path: /usr/include

  Could not find the following Boost libraries:

          boost_program_options
          boost_system
          boost_thread
          boost_unit_test_framework
...

So i tried to add the boost dir in the toolchain file :

set(BOOST_LIBRARYDIR "/usr/lib/x86_64-linux-gnu")

And it workd for the boost libraries but another error pops

-- Boost version: 1.65.1
-- Found the following Boost libraries:
--   program_options
--   system
--   thread
--   unit_test_framework
--   chrono
--   date_time
--   atomic

...

-- Configuring done
WARNING: Target "kenlm_util" requests linking to directory "/usr/lib/x86_64-linux-gnu".  Targets may link only to libraries.  CMake is dropping the item.
WARNING: Target "probing_hash_table_benchmark" requests linking to directory "/usr/lib/x86_64-linux-gnu".  Targets may link only to libraries.  CMake is dropping the item.
WARNING: Target "query" requests linking to directory "/usr/lib/x86_64-linux-gnu".  Targets may link only to libraries.  CMake is dropping the item.
WARNING: Target "fragment" requests linking to directory "/usr/lib/x86_64-linux-gnu".  Targets may link only to libraries.  CMake is dropping the item.
WARNING: Target "kenlm" requests linking to directory "/usr/lib/x86_64-linux-gnu".  Targets may link only to libraries.  CMake is dropping the item.
WARNING: Target "build_binary" requests linking to directory "/usr/lib/x86_64-linux-gnu".  Targets may link only to libraries.  CMake is dropping the item.
WARNING: Target "kenlm_benchmark" requests linking to directory "/usr/lib/x86_64-linux-gnu".  Targets may link only to libraries.  CMake is dropping the item.
WARNING: Target "lmplz" requests linking to directory "/usr/lib/x86_64-linux-gnu".  Targets may link only to libraries.  CMake is dropping the item.
WARNING: Target "count_ngrams" requests linking to directory "/usr/lib/x86_64-linux-gnu".  Targets may link only to libraries.  CMake is dropping the item.
WARNING: Target "kenlm_builder" requests linking to directory "/usr/lib/x86_64-linux-gnu".  Targets may link only to libraries.  CMake is dropping the item.
WARNING: Target "filter" requests linking to directory "/usr/lib/x86_64-linux-gnu".  Targets may link only to libraries.  CMake is dropping the item.
WARNING: Target "phrase_table_vocab" requests linking to directory "/usr/lib/x86_64-linux-gnu".  Targets may link only to libraries.  CMake is dropping the item.
WARNING: Target "streaming_example" requests linking to directory "/usr/lib/x86_64-linux-gnu".  Targets may link only to libraries.  CMake is dropping the item.
WARNING: Target "interpolate" requests linking to directory "/usr/lib/x86_64-linux-gnu".  Targets may link only to libraries.  CMake is dropping the item.
-- Generating done

I've been trying many things to make it work like set(LINK_DIRECTORIES), set(CMAKE_INCLUDE_PATH), set(Boost_LIBRARY_DIRS) (to add multiple boost dirs), set(KENLM_ROOT_DIR), set(KENLM_LIB), set(KENLM_UTIL_LIB), set(KENLM_INC)

Nothing worked, and i've been searching for a while know, so if you have some hints it would be great

-----------------------------------------------------------------------------------------------------------------------------------

**EDIT : I compiled boost for android but I dont succeed to do that with bzip2, I know have an error of this style **

-- Found BZip2: /usr/local/lib/libbz2.a (found version "1.0.8") 
-- Looking for BZ2_bzCompressInit
-- Looking for BZ2_bzCompressInit - not found