Mac Build Issue with glfw3

[pmaine]

I am running the Catalina operating system. Here are the steps that I followed:

1. Installed Homebrew
   2.brew install fftw glew glfw volk airspy airspyhf portaudio hackrf rtl-sdr libbladerf
2. Cloned SDRPlusPlus and cd into SDRPlusPlus directory
3. mkdir build
4. cmake ..

cmake returns the following error:
Pauls-Mac-mini:build pmaine$ cmake ..
-- Checking for module 'glfw3'
-- No package 'glfw3' found
CMake Error at /opt/local/share/cmake-3.18/Modules/FindPkgConfig.cmake:545 (message):
A required package was not found
Call Stack (most recent call first):
/opt/local/share/cmake-3.18/Modules/FindPkgConfig.cmake:733 (_pkg_check_modules_internal)
core/CMakeLists.txt:64 (pkg_check_modules)

-- Configuring incomplete, errors occurred!

Your assistance is appreciated.