... I did get the following error after step 4.2 and not sure how to proceed:

Michaels-MacBook-Pro:build michaelwickson$ cmake ..
-- [hunter] Initializing Hunter workspace (aafb99b93d466f963d53a39271f20d5074996cb0)
-- [hunter] https://github.com/ruslo/hunter/archive/v0.19.86.tar.gz
-- [hunter] -> /Users/michaelwickson/.hunter/_Base/Download/Hunter/0.19.86/aafb99b
xcrun: error: invalid active developer path (/Library/Developer/CommandLineTools), missing xcrun at: /Library/Developer/CommandLineTools/usr/bin/xcrun

[hunter ** INTERNAL **] Build project failed
[hunter ** INTERNAL **] [Directory:/Users/michaelwickson/Applications/ethminer]

------------------------------ WIKI -------------------------------
https://github.com/ruslo/hunter/wiki/error.internal

CMake Error at cmake/HunterGate.cmake:82 (message):
Call Stack (most recent call first):
cmake/HunterGate.cmake:92 (hunter_gate_wiki)
cmake/HunterGate.cmake:346 (hunter_gate_internal_error)
cmake/HunterGate.cmake:510 (hunter_gate_download)
CMakeLists.txt:12 (HunterGate)

-- Configuring incomplete, errors occurred!