[gtk+/gtk-3-22] gl: Check for GL_EXT_framebuffer_blit before using glBlitFramebuffer

[Emmanuele Bassi <ebassi src gnome org>]

commit 33e4826efd7c77296682c022b75eec8a5ee1ec94
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Wed Dec 14 18:30:16 2016 +0000

    gl: Check for GL_EXT_framebuffer_blit before using glBlitFramebuffer
    
    We check when we realize the GdkGLContext, but we never use the check
    before using the API, and it breaks on drivers that do not implement the
    extension, or on drivers that only support OpenGL ES 2.0.

 gdk/gdkgl.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/gdk/gdkgl.c b/gdk/gdkgl.c
index 51d2b02..8e7b8c2 100644
--- a/gdk/gdkgl.c
+++ b/gdk/gdkgl.c
@@ -409,6 +409,7 @@ gdk_cairo_draw_from_gl (cairo_t              *cr,
       alpha_size == 0 &&
       direct_window != NULL &&
       direct_window->current_paint.use_gl &&
+      gdk_gl_context_has_framebuffer_blit (paint_context) &&
       trivial_transform &&
       clip_region != NULL)
     {