Make read-only globals const, additional fixes

- Global variables that are never written to are marked const
- Remove some EXTERN declaration
- Remove unused `log_mem_multi` from logging module

openair2/UTIL/OPT/probe.c

@@ -101,14 +101,15 @@ int opt_enabled=0;
 //static unsigned int g_PDUOffset;
 
 FILE *file_fd = NULL;
-pcap_hdr_t file_header = {
-  0xa1b2c3d4,   /* magic number */
-  2, 4,         /* version number is 2.4 */
-  0,            /* timezone */
-  0,            /* sigfigs - apparently all tools do this */
-  65535,        /* snaplen - this should be long enough */
-  DLT_IPV4
-  //MAC_LTE_DLT   /* Data Link Type (DLT).  Set as unused value 147 for now */
+const pcap_hdr_t file_header = {
+    0xa1b2c3d4, /* magic number */
+    2,
+    4, /* version number is 2.4 */
+    0, /* timezone */
+    0, /* sigfigs - apparently all tools do this */
+    65535, /* snaplen - this should be long enough */
+    DLT_IPV4
+    // MAC_LTE_DLT   /* Data Link Type (DLT).  Set as unused value 147 for now */
 };
 
 trace_mode_t opt_type = OPT_NONE;