> The way to get the Homebrew-installed location of a given package is (here) brew --prefix giflib, which would avoid needing the "locate" stuff.

I know this node is old but it might be wrong so let's go.

Thanks etj but --prefix doesn't seem to return the requred paths:

% brew --prefix giflib
/opt/homebrew/opt/giflib

% ls -l /opt/homebrew/opt/giflib
lrwxr-xr-x /opt/homebrew/opt/giflib -> ../Cellar/giflib/5.2.2

Required:

--incpath=/opt/homebrew/include 
--libpath=/opt/homebrew/var/homebrew/linked/giflib/lib