It doesn’t appear you have the build tools including clang available.
The xcode-select install command shown below is needed once, and installs the build tools.
Supposedly, this is the Homebrew install sequence:
xcode-select --install
brew remove portaudio
brew install portaudio
pip3 install pyaudio
If you don’t have Homebrew installed, the directions for installing that are here:
https://brew.sh/
I’d suggest contacting whoever is maintaining the pyAudio port for assistance, if your difficulties here persist..
https://people.csail.mit.edu/hubert/pyaudio/
That webpage also indicates you need PyAudio 0.2.13 or later for Apple silicon.