Windows generates Ctrl + Alt_R for AltGr. By removing the Ctrl modifier Linux
guests see AltGr. This fixes e.g. the '~' key on german keyboards.

Signed-off-by: Bernhard Beschow <shentey@gmail.com>
---
 ui/sdl2-input.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/ui/sdl2-input.c b/ui/sdl2-input.c
index f068382209..a6538b56d2 100644
--- a/ui/sdl2-input.c
+++ b/ui/sdl2-input.c
@@ -39,6 +39,19 @@ void sdl2_process_key(struct sdl2_console *scon,
         return;
     }
     qcode = qemu_input_map_usb_to_qcode[ev->keysym.scancode];
+
+#ifdef CONFIG_WIN32
+    if (qcode == Q_KEY_CODE_ALT_R &&
+        qkbd_state_modifier_get(scon->kbd, QKBD_MOD_CTRL)) {
+        /*
+         * Windows generates Ctrl + Alt_R for AltGr. By removing the Ctrl
+         * modifier (Linux) guests see AltGr.
+         */
+        trace_sdl2_process_key(ev->keysym.scancode, Q_KEY_CODE_CTRL, "up");
+        qkbd_state_key_event(scon->kbd, Q_KEY_CODE_CTRL, false);
+    }
+#endif
+
     trace_sdl2_process_key(ev->keysym.scancode, qcode,
                            ev->type == SDL_KEYDOWN ? "down" : "up");
     qkbd_state_key_event(scon->kbd, qcode, ev->type == SDL_KEYDOWN);
-- 
2.40.0