can't build photon in x86_64

[BigVan]

# cmake -B build
-- Checking dependency zlib
-- Will find zlib
-- Checking dependency openssl
-- Will find openssl
-- Checking dependency aio
-- Will find aio
-- Checking dependency curl
-- Will find curl
-- Checking dependency gflags
-- Will find gflags
-- Checking dependency googletest
-- Will find googletest
-- The ASM_NASM compiler identification is unknown
-- Didn't find assembler
CMake Error at common/checksum/test/CMakeLists.txt:5 (enable_language):
  No CMAKE_ASM_NASM_COMPILER could be found.

  Tell CMake where to find the compiler by setting either the environment
  variable "ASM_NASM" or the CMake cache entry CMAKE_ASM_NASM_COMPILER to the
  full path to the compiler, or to the compiler name if it is in the PATH.


-- Configuring incomplete, errors occurred!

[lihuiba]

you need to install nasm in order to build unit tests.