Hi Jules!
void FloatVectorOperations::negate (float* dest, const float* src, int num) noexcept
{
#if JUCE_USE_VDSP_FRAMEWORK
vDSP_vneg (src, 1, dest, 1, num);
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.8.sdk/System/Library/Frameworks/vecLib.framework/Headers/vDSP.h:6427:1: Candidate function not viable: 1st argument ('const float *') would lose const qualifier
You're passing-in const float * for src, but the function expects a plain float* ...
Looks like just a simple cast will fix it.
vDSP_vneg (const_cast<float*>(src), 1, dest, 1, num);
I saw this just now, using XCode 5, with the tip from the Juce repo.
HTH!
Pete