create dft shared lib

cmake_targets/CMakeLists.txt

openair1/PHY/LTE_ESTIMATION/lte_adjust_sync_eNB.c

openair1/PHY/LTE_ESTIMATION/lte_sync_time.c

openair1/PHY/LTE_ESTIMATION/lte_ul_channel_estimation.c

openair1/PHY/LTE_TRANSPORT/prach.c

openair1/PHY/LTE_TRANSPORT/ulsch_demodulation.c

openair1/PHY/MODULATION/ofdm_mod.c

openair1/PHY/MODULATION/slot_fep_nr.c

openair1/PHY/MODULATION/slot_fep_ul.c

openair1/PHY/TOOLS/oai_dfts.c

openair1/PHY/TOOLS/tools_defs.h