init-cpm.cmake

set(CPM_REPOSITORY https://github.com/iauns/cpm)
set(CPM_DIR "${CMAKE_CURRENT_BINARY_DIR}/cpm_packages" CACHE TYPE STRING)
find_package(Git)
if(NOT GIT_FOUND)
  message(FATAL_ERROR "CPM requires Git.")
endif()
if ((NOT DEFINED CPM_MODULE_CACHE_DIR) AND (NOT "$ENV{CPM_CACHE_DIR}" STREQUAL ""))
  set(CPM_MODULE_CACHE_DIR "$ENV{CPM_CACHE_DIR}")
endif()
if ((NOT EXISTS ${CPM_DIR}/CPM.cmake) AND (DEFINED CPM_MODULE_CACHE_DIR))
  if (EXISTS "${CPM_MODULE_CACHE_DIR}/github_iauns_cpm")
    message(STATUS "Found cached version of CPM.")
    file(COPY "${CPM_MODULE_CACHE_DIR}/github_iauns_cpm/" DESTINATION ${CPM_DIR})
  endif()
endif()
if (NOT EXISTS ${CPM_DIR}/CPM.cmake)
  message(STATUS "Cloning repo (${CPM_REPOSITORY})")
  execute_process(
    COMMAND "${GIT_EXECUTABLE}" clone ${CPM_REPOSITORY} ${CPM_DIR}
    RESULT_VARIABLE error_code
    OUTPUT_QUIET ERROR_QUIET)
  if(error_code)
    message(FATAL_ERROR "CPM failed to get the hash for HEAD")
  endif()
endif()
include(${CPM_DIR}/CPM.cmake)