The integration of entangled into other CMake or Makefile projects is quite complicated.
The commands to build the static libraries are too complicated. The following command is needed

bazel build -c opt --crosstool_top=@iota_toolchains//tools/x86-64-core-i7--glibc--bleeding-edge-2018.07-1:toolchain --cpu='x86_64' --compiler='gcc' --host_crosstool_top=@bazel_tools//tools/cpp:toolchain //mam/api

in order to cross compile a library. I recommend compiling static and share libraries in the release process.