Use HOMEBREW_PREFIX to locate Homebrew

[RA80533]

Fixes #1211

[RA80533]

@mkleehammer What can I do to bring this over the finish line?

[coreyo]

Please consider this. Why has it been ignored for years now? You cannot install this package on MacOS using tools like pip without manually downloading it and setting extra environment variables:
https://whodeenie.medium.com/installing-pyodbc-and-unixodbc-for-apple-silicon-8e238ed7f216

I currently do the following to make the package work:

pip uninstall pyodbc
export CPPFLAGS="-I/opt/homebrew/include"
export LDFLAGS="-L/opt/homebrew/lib -liodbc -liodbcinst"
cd path/to/pyodbc-X.X.X.tar.gz
pip install pyodbc-X.X.X.tar.gz