This only affects Wayland and DirectFB, as a Unix system generally has X11
support. Other platforms also have different sizes for the C union in
question, but are likely the only target for that platform, etc.
Apps that might run on Wayland or DirectFB will need to be compiled against
new headers from an official 2.0.6 release, or be prepared to force the x11
target, or not use SDL_GetWindowWMInfo().
Fixes Bugzilla #3428.
This is currently implemented for X11, Cocoa, Windows, and DirectFB.
This patch is based on work in Unreal Engine 4's fork of SDL,
compliments of Epic Games.
The internal function SDL_EGL_LoadLibrary() did not delete and remove a mostly
uninitialized data structure if loading the library first failed. A later try to
use EGL then skipped initialization and assumed it was previously successful
because the data structure now already existed. This led to at least one crash
in the internal function SDL_EGL_ChooseConfig() because a NULL pointer was
dereferenced to make a call to eglBindAPI().
