Split to silk_biquad_alt_stride1() and silk_biquad_alt_stride2(),
so that it can be optimized more efficiently when stride is 2.
This change in C code is bit exact with the origin.
Change-Id: Idaefe670397016ace2a489e3435ac61b7dbe79d5
Signed-off-by: Jean-Marc Valin <jmvalin@jmvalin.ca>
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.
