Completion files are not installed to Homebrew Cellar

[Myridium]

$ make install PREFIX="$(brew --cellar)/passage/dev"
install: mkdir /opt/homebrew/Cellar/passage
install: mkdir /opt/homebrew/Cellar/passage/dev
install: mkdir /opt/homebrew/Cellar/passage/dev/lib
install: mkdir /opt/homebrew/Cellar/passage/dev/lib/passage
install: src/platform/darwin.sh -> /opt/homebrew/Cellar/passage/dev/lib/passage/platform.sh
install: mkdir /opt/homebrew/Cellar/passage/dev/lib/passage/extensions
install: mkdir /opt/homebrew/Cellar/passage/dev/bin
install: src/.passage -> /opt/homebrew/Cellar/passage/dev/bin/passage

[FiloSottile]

Hmm, that's because autodetection is looking inside the prefix, which doesn't work with Homebrew's symlinking approach.

passage/Makefile

Lines 8 to 10 in a42b9c1

	BASHCOMPDIR ?= $(PREFIX)/share/bash-completion/completions
	ZSHCOMPDIR ?= $(PREFIX)/share/zsh/site-functions
	FISHCOMPDIR ?= $(PREFIX)/share/fish/vendor_completions.d/

The best solution might be to just autodetect installation to the Homebrew Cellar.