SDL_JOYDEVICEADDED events must contain the device index which is a value between
0 and the number of connected joysticks. The old implementation included a value
based on the instance id instead. It worked in some cases because the values are
similar initially. But after disconnecting joysticks this is no more the case
and the always increasing instance id becomes larger than number of joysticks.
Jonas Kulla
The configure script didn't differentiate between Linux and Android, unconditionally compiling in the unix implementation of SDL_sysfilesystem.c.
I'm probably one of the very few people building SDL for android using classic configure + standalone toolchain, so this has gone undetected all along.