set(CMAKE_SYSTEM_NAME Linux)
set(CMAKE_SYSTEM_PROCESSOR x86_64)

set(CMAKE_C_COMPILER gcc)
set(CMAKE_CXX_COMPILER g++)

set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -m64" CACHE STRING "c++ flags")
set(CMAKE_C_FLAGS   "${CMAKE_C_FLAGS} -m64" CACHE STRING "c flags")