Aaron Barany
I realized I made a minor mistake in my patch: I changed the constructor prototype for SDL_DisplayData, but didn't update the declaration in the .h file. The compiler and linker don't complain, but it would probably be best to fix in case a later change runs into a problem from the mismatch. I have attached a patch to fix this.
Aaron Barany
There appears to be no way to directly access the display DPI on iOS, so as an approximation the DPI for the iPhone 1 is used as a base value and is multiplied by the screen's scale. This should at least give a ballpark number for the various screen scales. (based on https://stackoverflow.com/questions/25756087/detecting-iphone-6-6-screen-sizes-in-point-values it appears that both 2x and 3x are used)
I have updated the patch to use a table of current devices and use a computation as a fallback. I have also updated the fallback computation to be more accurate.
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().
