[PATCH] SDL: enable OpenGL context creation

[Jan Henrik Weinstock]

We need to specify SDL_WINDOW_OPENGL if we want to create an OpenGL 
context on it, i.e. when using '-device virtio-gpu-pci,virgl=on'

Signed-off-by: Jan Henrik Weinstock <jan.weinstock@rwth-aachen.de>
---
 ui/sdl2.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/ui/sdl2.c b/ui/sdl2.c
index abad7f981e..189d26e2a9 100644
--- a/ui/sdl2.c
+++ b/ui/sdl2.c
@@ -84,6 +84,11 @@ void sdl2_window_create(struct sdl2_console *scon)
     if (scon->hidden) {
         flags |= SDL_WINDOW_HIDDEN;
     }
+#ifdef CONFIG_OPENGL
+    if (scon->opengl) {
+        flags |= SDL_WINDOW_OPENGL;
+    }
+#endif

     scon->real_window = SDL_CreateWindow("", SDL_WINDOWPOS_UNDEFINED,
                                          SDL_WINDOWPOS_UNDEFINED,
--
2.17.1