vnc: Initialization stubs

This reduces the number of CONFIG_VNC #ifdefs in the vl.c code.

The only user-visible difference is that this will make QEMU
complain about syntax when using "-display vnc" ("VNC requires a
display argument vnc=<display>") even if CONFIG_VNC is disabled.
Signed-off-by: NEduardo Habkost <ehabkost@redhat.com>

include/ui/console.h

@@ -6,6 +6,8 @@
 #include "qapi/qmp/qdict.h"
 #include "qemu/notify.h"
 #include "qapi-types.h"
+#include "qemu/error-report.h"
+#include "qapi/error.h"
 
 #ifdef CONFIG_OPENGL
 # include <epoxy/gl.h>
@@ -430,10 +432,10 @@ void cocoa_display_init(DisplayState *ds, int full_screen);
 void vnc_display_init(const char *id);
 void vnc_display_open(const char *id, Error **errp);
 void vnc_display_add_client(const char *id, int csock, bool skipauth);
-char *vnc_display_local_addr(const char *id);
 #ifdef CONFIG_VNC
 int vnc_display_password(const char *id, const char *password);
 int vnc_display_pw_expire(const char *id, time_t expires);
+char *vnc_display_local_addr(const char *id);
 QemuOpts *vnc_parse(const char *str, Error **errp);
 int vnc_init_func(void *opaque, QemuOpts *opts, Error **errp);
 #else
@@ -445,6 +447,22 @@ static inline int vnc_display_pw_expire(const char *id, time_t expires)
 {
     return -ENODEV;
 };
+static inline QemuOpts *vnc_parse(const char *str, Error **errp)
+{
+    error_setg(errp, "VNC support is disabled");
+    return NULL;
+}
+static inline int vnc_init_func(void *opaque, QemuOpts *opts, Error **errp)
+{
+    error_setg(errp, "VNC support is disabled");
+    return -1;
+}
+static inline char *vnc_display_local_addr(const char *id)
+{
+    /* This must never be called if CONFIG_VNC is disabled */
+    error_report("VNC support is disabled");
+    abort();
+}
 #endif
 
 /* curses.c */

vl.c

@@ -2148,7 +2148,6 @@ static DisplayType select_display(const char *p)
         exit(1);
 #endif
     } else if (strstart(p, "vnc", &opts)) {
-#ifdef CONFIG_VNC
         if (*opts == '=') {
             Error *err = NULL;
             if (vnc_parse(opts + 1, &err) == NULL) {
@@ -2159,10 +2158,6 @@ static DisplayType select_display(const char *p)
             error_report("VNC requires a display argument vnc=<display>");
             exit(1);
         }
-#else
-        error_report("VNC support is disabled");
-        exit(1);
-#endif
     } else if (strstart(p, "curses", &opts)) {
 #ifdef CONFIG_CURSES
         display = DT_CURSES;
@@ -2966,9 +2961,7 @@ int main(int argc, char **argv, char **envp)
     const char *qtest_log = NULL;
     const char *pid_file = NULL;
     const char *incoming = NULL;
-#ifdef CONFIG_VNC
     int show_vnc_port = 0;
-#endif
     bool defconfig = true;
     bool userconfig = true;
     const char *log_mask = NULL;
@@ -3715,17 +3708,12 @@ int main(int argc, char **argv, char **envp)
                 break;
             case QEMU_OPTION_vnc:
             {
-#ifdef CONFIG_VNC
                 Error *local_err = NULL;
 
                 if (vnc_parse(optarg, &local_err) == NULL) {
                     error_report_err(local_err);
                     exit(1);
                 }
-#else
-                error_report("VNC support is disabled");
-                exit(1);
-#endif
                 break;
             }
             case QEMU_OPTION_no_acpi:
@@ -4578,7 +4566,6 @@ int main(int argc, char **argv, char **envp)
     /* must be after terminal init, SDL library changes signal handlers */
     os_setup_signal_handling();
 
-#ifdef CONFIG_VNC
     /* init remote displays */
     qemu_opts_foreach(qemu_find_opts("vnc"),
                       vnc_init_func, NULL, NULL);
@@ -4587,7 +4574,7 @@ int main(int argc, char **argv, char **envp)
         printf("VNC server running on '%s'\n", ret);
         g_free(ret);
     }
-#endif
+
 #ifdef CONFIG_SPICE
     if (using_spice) {
         qemu_spice_display_init();