By default Visual Studio warns about various C stdlib calls,
recommending non-portable replacements instead. We disable
this warning in a number of places in the source.
Since they're specific to the Visual Studio build, it's better
to disable them just in the project files where they always
apply to the correct toolchain.
I have only added the disable setting to project files which
need it currently: opus, test_opus_encode, and test_opus_decode.
This warning disable was conditional on _WIN32, which mingw
also defines, resulting in a warning about the unknown pragma
on gcc. Instead make it depend on something only the Visual
Studio compiler defines.
C reserves identifiers of the from _[A-Z]+ and we have a number of
those in the code. This patch renames the various function arguments,
MACROS and preprocessor symbols to avoid the reserved form.
It also removes the CHANNELS() macro altogether. This was a
minor optimization for TI DSP to force a mono-only build,
as were the associated local 'const' versions. Since stereo
support is manditory, it wasn't worth keeping.
Thanks to John Ridges for raising the issue, and Jean-Marc Valin
and Greg Maxwell for reviewing the changes.
