This PR modifies the Makefile so that it will test both `/usr/local/opt` and `/opt/homebrew/opt` for finding the `curl` and `libzip` includes.
## Why the change?
Without this change, libzip and curl wouldn't be found on macOS M1 and compilation would not succeed. While I could have just included both folders without if structures, I wanted to avoid the makefile warning about not being able to find a directory.
## How can this be tested?
Run `make` on a system that has homebrew installed to `/opt/homebrew`, like macOS M1.
## Relevant tickets?
Closes #80
What does it do?