configure output is practically unchanged. there are still lots of
AC_TRY_COMPILE/AC_TRY_LINK replacements needed to really eliminate
the warnings, but that's for another time.
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().
