This is unoptimal but could be improved using C++11 (or memory barriers
for double check locking)
fixes #14885

hvc1 is reserved for streams with VCL only

bitstream reader will always return 0 if no bytes

Avoid linking with -lrt if not needed (e.g. recent GNU/libc),
simplify, and enable linking other library than libvlccore.

When not implicit, limits are mentioned in *_id description.

Useless then suspicious use in omxil.c might incur a regression.

Tries strongest match against decoder record

Like valgrind, the address sanitizer generates unusable leak reports if
plugins are unloaded.

Run 'make lcov' to produce the coverage report in the lcov/.
This requires lcov installed and the --enable-coverage configure flag.