[PATCH] qemu-options: Rework the help text of the '-display' option

[Thomas Huth <huth@tuxfamily.org>]

Improve the help text of the "-display" option:

- Only print the options that we have enabled in the binary
  (similar to what we do for other options like -netdev already)

- The "frame=on|off" from "-display sdl" has been removed in commit
  09bd7ba9f5f7 ("Remove deprecated -no-frame option"), so we should
  not show this in the help text anymore

- The "-display egl-headless" line was missing a "\n" at the end

- Indent the default display text in a nicer way

Signed-off-by: Thomas Huth <huth@tuxfamily.org>
---
 qemu-options.hx | 30 +++++++++++++++++++++---------
 1 file changed, 21 insertions(+), 9 deletions(-)

diff --git a/qemu-options.hx b/qemu-options.hx
index 996b6fba74..917c54b302 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -1526,26 +1526,38 @@ STEXI
 ETEXI
 
 DEF("display", HAS_ARG, QEMU_OPTION_display,
+#if defined(CONFIG_SPICE)
     "-display spice-app[,gl=on|off]\n"
-    "-display sdl[,frame=on|off][,alt_grab=on|off][,ctrl_grab=on|off]\n"
+#endif
+#if defined(CONFIG_SDL)
+    "-display sdl[,alt_grab=on|off][,ctrl_grab=on|off]\n"
     "            [,window_close=on|off][,gl=on|core|es|off]\n"
+#endif
+#if defined(CONFIG_GTK)
     "-display gtk[,grab_on_hover=on|off][,gl=on|off]|\n"
+#endif
+#if defined(CONFIG_VNC)
     "-display vnc=<display>[,<optargs>]\n"
+#endif
+#if defined(CONFIG_CURSES)
     "-display curses[,charset=<encoding>]\n"
+#endif
+#if defined(CONFIG_OPENGL)
+    "-display egl-headless[,rendernode=<file>]\n"
+#endif
     "-display none\n"
-    "-display egl-headless[,rendernode=<file>]"
-    "                select display type\n"
-    "The default display is equivalent to\n"
+    "                select display backend type\n"
+    "                The default display is equivalent to\n                "
 #if defined(CONFIG_GTK)
-            "\t\"-display gtk\"\n"
+            "\"-display gtk\"\n"
 #elif defined(CONFIG_SDL)
-            "\t\"-display sdl\"\n"
+            "\"-display sdl\"\n"
 #elif defined(CONFIG_COCOA)
-            "\t\"-display cocoa\"\n"
+            "\"-display cocoa\"\n"
 #elif defined(CONFIG_VNC)
-            "\t\"-vnc localhost:0,to=99,id=default\"\n"
+            "\"-vnc localhost:0,to=99,id=default\"\n"
 #else
-            "\t\"-display none\"\n"
+            "\"-display none\"\n"
 #endif
     , QEMU_ARCH_ALL)
 STEXI
-- 
2.21.0