flac: updated to 1.3.3

FLAC 1.3.3:

General:
- Fix CPU detection
- Switch from unsigned types to uint32_t
- CppCheck fixes
- Improve SIMD decoding of 24 bit files
- POWER* amnd POWER9 improvements
- More tests.

flac:
- When converting to WAV, use WAVEFORMATEXTENSIBLE when bits per second is not 8 or 16
- Fix --output-prefix with input-files in sub-directories

build system:
- Cmake support
- Visual Studio updates
- Fix for MSVC when UNICODE is enabled
- Fix for OpenBSD/i386

(adam)