error message if user specifies curses on cmd line when curses is disabled

Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

qemu-options.hx

@@ -634,11 +634,9 @@ the console. Therefore, you can still use QEMU to debug a Linux kernel
 with a serial console.
 ETEXI
 
-#ifdef CONFIG_CURSES
 DEF("curses", 0, QEMU_OPTION_curses,
     "-curses         use a curses/ncurses interface instead of SDL\n",
     QEMU_ARCH_ALL)
-#endif
 STEXI
 @item -curses
 @findex curses

vl.c

@@ -2247,11 +2247,14 @@ int main(int argc, char **argv, char **envp)
             case QEMU_OPTION_nographic:
                 display_type = DT_NOGRAPHIC;
                 break;
-#ifdef CONFIG_CURSES
             case QEMU_OPTION_curses:
+#ifdef CONFIG_CURSES
                 display_type = DT_CURSES;
-                break;
+#else
+                fprintf(stderr, "Curses support is disabled\n");
+                exit(1);
 #endif
+                break;
             case QEMU_OPTION_portrait:
                 graphic_rotate = 1;
                 break;