Fixes problems launching Firewatch on Linux (which statically links SDL but
also dynamically loads a system-wide copy from a plugin shared library) with
a newer SDL build.
SDL now builds with gcc 7.2 with the following command line options:
-Wall -pedantic-errors -Wno-deprecated-declarations -Wno-overlength-strings --std=c99
Kai Sterker
SDL2 on Haiku so far uses Haiku-specific APIs for loading dynamic objects as add-ons, instead of using dlopen to load them as libraries. This, for example, leads to SDL_mixer not being able to load its audio backends, when compiled with standard settings.
As discussed at https://www.freelists.org/post/haikuports/SDL2-mixer-ogg-music-not-playing-and-other-stuff,2 , the best way to deal with this would be using dlopen instead of load_add_on. The following patch implements this change by dropping the Haiku-specific bits and using dlopen instead.
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().
