Add support for overridable VM name

- A global variable added as vm_name
- This variable can be filled with the `--vmname "Name"` or `-V "Name"` parameter.
- If there are no such a parameter definied this variable will filled up with the directory name.
- The Discord module displays this global variable, as VM name.
- Various 86Box managers can use this feature to display fancy VM names, instead of GUID folder names.
- This variable can be easily used later for adding cool things, like the VM name in title bar, etc.

src/86box.c

@@ -110,6 +110,7 @@ uint64_t	unique_id = 0;
 uint64_t	source_hwnd = 0;
 #endif
 char	log_path[1024] = { '\0'};		/* (O) full path of logfile */
+char	vm_name[1024]  = { '\0'};		/* (O) display name of the VM */
 
 /* Configuration values. */
 int	window_w;   /* (C) window size and */
@@ -417,6 +418,7 @@ usage:
 			printf("-F or --fullscreen   - start in fullscreen mode\n");
 			printf("-L or --logfile path - set 'path' to be the logfile\n");
 			printf("-P or --vmpath path  - set 'path' to be root for vm\n");
+			printf("-V or --vmname name  - overrides the name of the running VM.\n");
 			printf("-S or --settings     - show only the settings dialog\n");
 			printf("-N or --noconfirm    - do not ask for confirmation on quit\n");
 #ifdef _WIN32
@@ -446,6 +448,11 @@ usage:
 			if ((c+1) == argc) goto usage;
 
 			strcpy(path, argv[++c]);
+		} else if (!strcasecmp(argv[c], "--vmname") ||
+			   !strcasecmp(argv[c], "-V")) {
+			if ((c+1) == argc) goto usage;
+
+			strcpy(vm_name, argv[++c]);
 		} else if (!strcasecmp(argv[c], "--settings") ||
 			   !strcasecmp(argv[c], "-S")) {
 			settings_only = 1;
@@ -551,6 +558,20 @@ usage:
 	/* At this point, we can safely create the full path name. */
 	plat_append_filename(cfg_path, usr_path, p);
 
+	/*
+     * Get the current directory's name
+	 *
+	 * At this point usr_path is perfectly initialized.
+	 * If no --vmname parameter specified we'll use the
+	 *   working directory name as the VM's name.
+	 */
+    if (strlen(vm_name) == 0)
+	{
+		plat_get_dirname(vm_name, usr_path);
+		p = plat_get_filename(vm_name);
+		strcpy(vm_name, p);
+	}
+
 	/*
 	 * This is where we start outputting to the log file,
 	 * if there is one. Create a little info header first.