Newer versions of MSVC are unhappy with the strategy of the build
environment redefining "inline" (even though they don't support the
actual keyword). Instead we define OPUS_INLINE to the right thing
in opus_defines.h.
This is the same approach we use for restrict.
This makes all remaining large stack allocations use the vararray
macros.
This continues the work of 6f2d9f50 to allow compiling with
NONTHREADSAFE_PSEUDOSTACK to move the memory for large buffers
off the stack for devices where it is very limited.
It also does this for some additional large buffers used by the
PLC in the decoder.
