fbdev: Fix compilation without EGL

We have to duplicate #defines and typedefs for the EGL types and constants
we use in gl-renderer.h so we can compile the fbdev backend without EGL.

https://bugs.freedesktop.org/show_bug.cgi?id=70392

src/gl-renderer.h

@@ -56,6 +56,7 @@ typedef void *EGLDisplay;
 typedef void *EGLSurface;
 typedef intptr_t EGLNativeDisplayType;
 typedef intptr_t EGLNativeWindowType;
+#define EGL_DEFAULT_DISPLAY NULL
 
 static const EGLint gl_renderer_opaque_attribs[];
 static const EGLint gl_renderer_alpha_attribs[];