CodeQL fixes

- Fix CodeQL issues:
  - https://github.com/DNS-OARC/PacketQ/security/code-scanning/35
  - https://github.com/DNS-OARC/PacketQ/security/code-scanning/37
  - https://github.com/DNS-OARC/PacketQ/security/code-scanning/38
  - https://github.com/DNS-OARC/PacketQ/security/code-scanning/39
  - https://github.com/DNS-OARC/PacketQ/security/code-scanning/40

src/pcap.h

@@ -178,7 +178,7 @@ class Pcap_file {
                 m_packetbuffer = 0;
             }
             m_packetbuffer_len = len + 4096;
-            m_packetbuffer     = new unsigned char[m_packetbuffer_len];
+            m_packetbuffer     = new(std::nothrow) unsigned char[m_packetbuffer_len];
             if (!m_packetbuffer)
                 m_packetbuffer_len = 0;
         }

src/server.cpp

@@ -66,7 +66,7 @@ namespace httpd {
                            "Content-Type: %s\r\n"
                            "\r\n";
 
-    Server* g_server = 0;
+    static Server* g_server = 0;
 
     class SocketPool {
     public:
@@ -1165,7 +1165,7 @@ void start_server(int port, bool fork_me, const std::string& pcaproot, const std
         if (cnt < max_conn) {
             int c = server.get_connection();
             if (c > -1) {
-                Http_socket* s = new Http_socket(c);
+                Http_socket* s = new(std::nothrow) Http_socket(c);
                 if (s && s->failed()) {
                     syslog(LOG_ERR | LOG_USER, "failed to create socket");
                     delete s;

src/sql.cpp

@@ -2556,7 +2556,7 @@ Cc_func::Cc_func(const OP& op)
         }
     }
 
-    MMDB_s* mmdb = new MMDB_s;
+    MMDB_s* mmdb = new(std::nothrow) MMDB_s;
     if (!mmdb) {
         return;
     }
@@ -2648,7 +2648,7 @@ Asn_func::Asn_func(const OP& op)
         }
     }
 
-    MMDB_s* mmdb = new MMDB_s;
+    MMDB_s* mmdb = new(std::nothrow) MMDB_s;
     if (!mmdb) {
         return;
     }