Tested mc_att_control_m and mc_pos_control_m in jmavsim.OK.

makefiles/posix/config_posix_sitl.mk

src/modules/mc_att_control_multiplatform/mc_att_control.cpp

src/modules/mc_att_control_multiplatform/mc_att_control.h

...ules/mc_att_control_multiplatform/mc_att_control_main.cpp

..._att_control_multiplatform/mc_att_control_start_nuttx.cpp

src/modules/mc_pos_control_multiplatform/mc_pos_control.cpp

src/modules/mc_pos_control_multiplatform/mc_pos_control.h

...ules/mc_pos_control_multiplatform/mc_pos_control_main.cpp

..._pos_control_multiplatform/mc_pos_control_start_nuttx.cpp

src/platforms/posix/px4_layer/px4_posix_impl.cpp