mxshadowsrc: Hoist two variables into static context

For prefork we need the listen_socket and the filename in the threads,
so hoist these variables up into the static context.

mxshadowsrv.c

@@ -74,6 +74,8 @@ static char *shadow_buf = NULL;   // protected by shadow_mutex
 static struct stat statbuf;       // protected by shadow_mutex
 static SSL_CTX *ssl_ctx;
 static sem_t free_worker;
+static int listen_socket;
+static char *filename;
 #ifdef DEBUG_MAX_CONNECTS
 static int debug_remaining_connects = DEBUG_MAX_CONNECTS;
 #endif
@@ -239,7 +241,7 @@ int main(int argc, char **argv) {
         die_usage(argv[0]);
     if (optind+1 != argc)
         die_usage(argv[0]);
-    char *filename = argv[optind++];
+    filename = argv[optind++];
 
     SSL_CTX *_ssl_ctx _cleanup_(free_ssl_ctx) = SSL_CTX_new(TLS_server_method());
     if (_ssl_ctx == NULL) { psslerror("SSL_CTX_new"); return 1; }
@@ -248,7 +250,7 @@ int main(int argc, char **argv) {
     if (SSL_CTX_use_PrivateKey_file(ssl_ctx, key_file, SSL_FILETYPE_PEM) <= 0 ) { psslerror("SSL_CTX_use_PrivateKey_file"); return 1; }
     if (SSL_CTX_use_certificate_file(ssl_ctx, cert_file, SSL_FILETYPE_PEM) <= 0) { psslerror("SSL_CTX_use_certificate_file"); return 1; }
 
-    int listen_socket = socket(AF_INET, SOCK_STREAM, 0);
+    listen_socket = socket(AF_INET, SOCK_STREAM, 0);
     if (listen_socket == -1) { perror("socket"); return 1; }
 
     static int true = 1;