Fix MODULE_NAME for android

Fix MODULE_NAME for android

The modules concerned all had non unique names (e.g. flac for both
the decoder and the demuxer).

MODULE_NAME macro uses Makefile target to retrieve a unique name
This was broken in 20cdb051acbe12ffee1f52e2e15e566762f04949, as
explained by automake documentation:

 When using a per-target compilation flag, Automake will choose a
 different name for the intermediate object files.