Further cleanup: define oai_exit for 4G

The parent commit cleans up and groups oai_exit in one place,
nr-softmodem-common.h. Therefore, this 5G file is included in the 4G
defs_common.h (at least it's mostly 4G), which is not nice. Instead,
define oai_exit also in 4G softmodem-common.h, and include this in
defs_common.h. Remove the cyclic inclusion of defs_common.h in
softmodem-common.h, and resolve all subsequent errors around unknown
types and extern definition mismatches.

openair2/LAYER2/MAC/eNB_scheduler_fairRR.c

@@ -52,7 +52,6 @@
 
 #ifdef PHY_TX_THREAD
   extern volatile int16_t phy_tx_txdataF_end;
-  extern int oai_exit;
 #endif
 extern uint16_t sfnsf_add_subframe(uint16_t frameP, uint16_t subframeP, int offset);
 extern void add_subframe(uint16_t *frameP, uint16_t *subframeP, int offset);

openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_RA.c

@@ -48,7 +48,6 @@
 #include <executables/softmodem-common.h>
 extern RAN_CONTEXT_t RC;
 extern const uint8_t nr_slots_per_frame[5];
-extern uint16_t sl_ahead;
 
 // forward declaration of functions used in this file
 static void fill_msg3_pusch_pdu(nfapi_nr_pusch_pdu_t *pusch_pdu,

openair2/LAYER2/NR_MAC_gNB/gNB_scheduler_primitives.c

@@ -3021,7 +3021,7 @@ int nr_mac_get_reconfig_delay_slots(NR_SubcarrierSpacing_t scs)
   /* we previously assumed a specific "slot ahead" value for the PHY processing
    * time. However, we cannot always know it (e.g., third-party PHY), so simply
    * assume a tentative worst-case slot processing time */
-  const uint16_t sl_ahead = 10;
+  const int sl_ahead = 10;
   /* 16ms seems to be the most common: See 38.331 Tab 12.1-1 */
   int delay_ms = NR_RRC_RECONFIGURATION_DELAY_MS + NR_RRC_BWP_SWITCHING_DELAY_MS;
   return (delay_ms << scs) + sl_ahead;

openair2/PHY_INTERFACE/phy_stub_UE.c

@@ -74,7 +74,7 @@ extern nfapi_tx_request_pdu_t* tx_request_pdu[1023][NUM_NFAPI_SUBFRAME][10]; //T
 //extern int timer_frame;
 
 extern UE_RRC_INST *UE_rrc_inst;
-extern uint16_t sf_ahead;
+extern int sf_ahead;
 
 static eth_params_t         stub_eth_params;
 void Msg1_transmitted(module_id_t module_idP,uint8_t CC_id,frame_t frameP, uint8_t eNB_id);