if(NOT "$ENV{HOME}" STREQUAL "")
  if(TILDE_PATH MATCHES "~" OR NOT IS_ABSOLUTE "${TILDE_PATH}")
    message(SEND_ERROR "~ not expanded as expected:\n ${TILDE_PATH}")
  endif()

  if(TILDE_SLASH_PATH MATCHES "~" OR NOT IS_ABSOLUTE "${TILDE_SLASH_PATH}" OR NOT TILDE_SLASH_PATH MATCHES "/InHome$")
    message(SEND_ERROR "~/ not expanded as expected:\n ${TILDE_SLASH_PATH}")
  endif()
else()
  set(ENV{HOME} "${CMAKE_CURRENT_LIST_DIR}")
endif()

set(TILDE "" CACHE PATH "")
if(TILDE MATCHES "~" OR NOT IS_ABSOLUTE "${TILDE}")
  message(SEND_ERROR "~ not expanded as expected:\n ${TILDE}")
endif()

set(TILDE_SLASH "" CACHE PATH "")
if(TILDE_SLASH MATCHES "~" OR NOT IS_ABSOLUTE "${TILDE_SLASH}" OR NOT TILDE_SLASH MATCHES "/InHome$")
  message(SEND_ERROR "~/ not expanded as expected:\n ${TILDE_SLASH}")
endif()