feat / work with cross-compile

CMakeLists.txt

cmake_targets/cross-arm.cmake

common/utils/T/CMakeLists.txt

doc/BUILD.md

doc/README.md

doc/cross-compile.md

...ir1/PHY/CODING/nrLDPC_decoder/nrLDPC_tools/CMakeLists.txt

...LDPC_decoder/nrLDPC_tools/generator_bnProc/CMakeLists.txt

...coder/nrLDPC_tools/generator_bnProc_avx512/CMakeLists.txt

...LDPC_decoder/nrLDPC_tools/generator_cnProc/CMakeLists.txt

...coder/nrLDPC_tools/generator_cnProc_avx512/CMakeLists.txt