Log Message:
opusfile: Update to 0.12

Changes since the v0.11 release:

 * Fix stack overflow buffering out-of-sequence streams.
 * Fix possible divide-by-zero.
 * Fix issues with seeking in the win32 backend.
 * Fix an issue where the seek algorithm could be confused by stream data
   changing between reads.
 * Clean up compiler and scan-build warnings.
 * Avoid use of the deprecated ftime() function which has Y2038 problems.
 * Remove undefined behaviour memcpy(NULL) in op_read_native().
 * Visual Studio project files updated for libogg 1.3.4 library name
   change.
 * Various build systems updates.
 * Various integration and testing environment improvements.

This release is backward-compatible with the previous release. We
recommend all users upgrade.