dovecot: use Homebrew `curl`, patch out `-flat_namespace` (#88330)
dovecot: use Homebrew `curl`, patch out `-flat_namespace` (#88330)

Downloading the `pigeonhole` resource fails with system `curl`. I'm not
sure why this is needed for the resource only and not also the tarball,
but here we are.

We also apply one of our usual patches for the `-flat_namespace` bug.

This enables bottling on Monterey.
chrisfinazzo/homebrew-core,mfikes/homebrew-core,lemzwerg/homebrew-core,chrisfinazzo/homebrew-core,sjackman/homebrew-core,stgraber/homebrew-core,Homebrew/homebrew-core,nandub/homebrew-core,nbari/homebrew-core,adam-moss/homebrew-core,filcab/homebrew-core,adam-moss/homebrew-core,Homebrew/homebrew-core,sjackman/homebrew-core,filcab/homebrew-core,nbari/homebrew-core,stgraber/homebrew-core,mfikes/homebrew-core,zyedidia/homebrew-core,uyjulian/homebrew-core,lemzwerg/homebrew-core,cblecker/homebrew-core,makigumo/homebrew-core,cblecker/homebrew-core,uyjulian/homebrew-core,nandub/homebrew-core,zyedidia/homebrew-core,makigumo/homebrew-core