Revert "Remove multicast from rig_state structure as it breaks backwards compability on DLL with WSJT-X"

This didn't fix the DLL compatibility problem
This reverts commit 77d9d11f92.

include/hamlib/rig.h

@@ -2629,7 +2629,7 @@ struct rig_state {
     char client_version[32];  /*!<! Allow client to report version for compatibility checks/capability */
     freq_t offset_vfoa; /*!< Offset to apply to VFOA/Main set_freq */
     freq_t offset_vfob; /*!< Offset to apply to VFOB/Sub set_freq */
-//    struct multicast_s *multicast; /*!< Pointer to multicast server data */
+    struct multicast_s *multicast; /*!< Pointer to multicast server data */
 };
 
 //! @cond Doxygen_Suppress

src/multicast.c

@@ -13,7 +13,6 @@
 #endif
 #include "hamlib/rig.h"
 #include "misc.h"
-#if 0
 #include "multicast.h"
 
 #define RIG_MULTICAST_ADDR "224.0.0.1"
@@ -525,4 +524,3 @@ int main(int argc, char *argv[])
     return 0;
 }
 #endif
-#endif

src/rig.c

@@ -7599,7 +7599,6 @@ HAMLIB_EXPORT(void) sync_callback(int lock)
 void rig_lock(RIG *rig, int lock)
 {
 #ifdef HAVE_PTHREAD
-#if 0 //MULTICAST disabled as it breaks the DLL backwards compatibility
 
     if (rig->state.multicast == NULL) { return; } // not initialized yet
 
@@ -7621,7 +7620,6 @@ void rig_lock(RIG *rig, int lock)
     }
 
 #endif
-#endif
 
 }
 

tests/rigtestmcast.c

@@ -31,9 +31,9 @@ int main(int argc, char *argv[])
 #endif
     rig->state.rigport.parm.serial.rate = 38400;
     rig_open(rig);
-//    multicast_init(rig, "224.0.0.1", 4532);
-    //printf("threadid=%lld\n", (long long)rig->state.multicast->threadid);
-    //pthread_join(rig->state.multicast->threadid, NULL);
+    multicast_init(rig, "224.0.0.1", 4532);
+    printf("threadid=%lld\n", (long long)rig->state.multicast->threadid);
+    pthread_join(rig->state.multicast->threadid, NULL);
     pthread_exit(NULL);
     return 0;
 }