* fix mac build

* add notes

* fix_mac_build

* update

add inference api demo impl

Check the system requirements

1. Add option WITH_AMD_GPU.
2. Add cmake/hip.cmake for HIP toolchain.
3. Some external module such as eigen may need HIP port.
4. Add macro hip_library/hip_binary/hip_test to cmake/generic.cmake.
5. Add one HIP source concat.hip.cu as an example. Each .cu may have its corresponding .hip.cu.

1. Add option WITH_AMD_GPU.
2. Add cmake/hip.cmake for HIP toolchain.
3. Some external module such as eigen may need HIP port.
4. Add macro hip_library/hip_binary/hip_test to cmake/generic.cmake.
5. Add one HIP source concat.hip.cu as an example. Each .cu may have its corresponding .hip.cu.

* Get rid of the dependency of Go compiler when WITH_GOLANG is OFF.

* Minor modification to the documentation.

* Remove the downloading and installing of Go compiler when build developing Docker image for android.

* Minor modifcation to the documentation's format.

* Change the default value of WITH_GOLANG to OFF in paddle/scripts/docker/build.sh.

* compile with nccl2

* add ncclGroup; it is necessary in nccl2

* add back libnccl-dev