[opus] "opus will be very slow" message

[Andrew P. Lentvorski]

I get the following message when cross compiling Opus 1.2.1 for android
with clang in a standalone build.

  CC       src/opus_decoder.lo
src/opus_decoder.c:37:10: warning: You appear to be compiling without
optimization, if so opus will be very slow. [-W#pragma-messages]
# pragma message "You appear to be compiling without optimization, if so
opus will be very slow."

Looking at the lines in question I see:

#if defined(__GNUC__) && (__GNUC__ >= 2) && !defined(__OPTIMIZE__) &&
!defined(OPUS_WILL_BE_SLOW)
# pragma message "You appear to be compiling without optimization, if so
opus will be very slow."
#endif

A quick find/grep, however, shows no place where __OPTIMIZE__ or
OPUS_WILL_BE_SLOW are actually defined--so presumably I would have to
pass them in.  And the only place __OPTIMIZE__ is *used* is in x86cpu.h,
so why isn't the warning over in that file?

What am I missing?  Presumably I can ignore that warning?

Thanks,
-a