Replace deprecated `-Ofast` with `-O3 -ffast-math`

[bosterho]

Hi, I've been looking into the warnings while using Pamplejuce. I see this whenever I compile:

clang++: warning: argument '-Ofast' is deprecated; use '-O3 -ffast-math' for the same behavior, or '-O3' to enable only conforming optimizations [-Wdeprecated-ofast]

In SharedCodeDefaults.cmake, if you do -03 -ffast-math instead of -Ofast that gets rid of the warning.

[bosterho]

Ah, actually I'm seeing this is kind of a sticky issue: https://forum.juce.com/t/is-fast-math-supported-with-juce/65793

I need to look into this more thoroughly... Maybe better to leave it to people to decide case-by-case.

You could "Close as Not Planned" maybe.