message: Fix linker error of missing pthread on Linux
diff: @@ -8,6 +8,10 @@ project(${TARGET_NAME} LANGUAGES CXX)
  set(CMAKE_CXX_STANDARD 14)
  set(CMAKE_CXX_STANDARD_REQUIRED True)
  +set(CMAKE_THREAD_PREFER_PTHREAD TRUE)
  +set(THREADS_PREFER_PTHREAD_FLAG TRUE)
  +find_package(Threads REQUIRED)
  +
  # min version for `CURLSSLOPT_NO_REVOKE`
  # https://curl.haxx.se/libcurl/c/CURLOPT_SSL_OPTIONS.html
  set(CURL_MIN_REQUIRED_VERSION 7.44)
  @@ -58,7 +62,7 @@ add_library (Azure::Core ALIAS ${TARGET_NAME})
  create_code_coverage(core ${TARGET_NAME} "${TARGET_NAME}-test")
  target_include_directories(${TARGET_NAME} PUBLIC ${CURL_INCLUDE_DIRS})
  -target_link_libraries(${TARGET_NAME} PRIVATE CURL::libcurl)
  +target_link_libraries(${TARGET_NAME} PRIVATE CURL::libcurl Threads::Threads)
  get_az_version("${CMAKE_CURRENT_SOURCE_DIR}/inc/azure/core/version.hpp")
  generate_documentation(azure-core ${AZ_LIBRARY_VERSION})
  