This is work from FS#12431 synced to current HEAD and slightly
tweaked (gcc 4.6.2 -> 4.6.3, binutils 2.21.1 -> 2.22)
Change-Id: I76af91e80ac2a9c16a776c7f0a33cc51603bbf9b
Use generic void * and size_t and make mp3_play_data and its callback
agree on types. Use mp3_play_callback_t instead of prototyping
right in the function call (so it's not so messy to look at). Change
doesn't appear to require plugin API version increment.
Change-Id: Idcab2740ee316a2beb6e0a87b8f4934d9d6b3dd8
