ZMQ radio

This commit introduces ZMQ-based radio library. Each pair of RX/TX antennas is
represented by a ZMQ REQ/REP socket pair which streams continuous IQ samples
from radio start until stop.

Usage:
Simplest configuration is to connect OAI NR UE to OAI GNB with the same number
of antennas - by inverting the RX and TX channels in ZMQ radio configuration the
gNBs TX is mapped to UEs RX antennas and vice versa.

common/config/config_load_configmodule.c

@@ -282,12 +282,9 @@ configmodule_interface_t *load_configmodule(int argc,
       cfgmode = strdup(CONFIG_LIBCONFIGFILE);
     }
   }
-  static configmodule_interface_t *cfgptr = NULL;
-  if (cfgptr)
-    fprintf(stderr, "ERROR: Call load_configmodule more than one time\n");
 
   // The macros are not thread safe print_params and similar
-  cfgptr = calloc(sizeof(configmodule_interface_t), 1);
+  configmodule_interface_t *cfgptr = calloc(sizeof(configmodule_interface_t), 1);
   if (!cfgptr) {
     fprintf(stderr, "ERROR: cannot allocate a memory for configuration\n");
     return NULL;

common/config/config_load_configmodule.h

@@ -10,6 +10,9 @@
 #ifndef INCLUDE_CONFIG_LOADCONFIGMODULE_H
 #define INCLUDE_CONFIG_LOADCONFIGMODULE_H
 
+#ifdef __cplusplus
+extern "C" {
+#endif
 
 #include <string.h>
 #include <stdlib.h>
@@ -117,5 +120,8 @@ void write_parsedcfg(configmodule_interface_t *cfg);
 extern void free_configmodule(void);
 #define CONFIG_PRINTF_ERROR(f, x... ) if (isLogInitDone ()) { LOG_E(ENB_APP,f,x);} else {printf(f,x);}; if ( !CONFIG_ISFLAGSET(CONFIG_NOABORTONCHKF) ) exit_fun("exit because configuration failed\n");
 
+#ifdef __cplusplus
+}
+#endif
 
 #endif  /* INCLUDE_CONFIG_LOADCONFIGMODULE_H */

common/config/config_paramdesc.h

@@ -181,6 +181,11 @@ typedef struct paramdef {
   {                                                                                                                          \
     OPTNAME(name), HELPSTR(help), PARAMFLAG(flags), .u64ptr = ptr, .defuintval = defval, PARAMTYPE(TYPE_UINT64), .numelt = 0 \
   }
+#define STRINGLISTPARAM(name, help, flags, ptr, defval)                                                                 \
+  {                                                                                                                     \
+    OPTNAME(name), HELPSTR(help), PARAMFLAG(flags), .strptr = ptr, .defstrlistval = defval, PARAMTYPE(TYPE_STRINGLIST), \
+        .numelt = 0                                                                                                     \
+  }
 
 typedef struct paramlist_def {
   char listname[MAX_OPTNAME_SIZE];