Update BUILD-INSTRUCTIONS-MACOS.md

[mmitevski]

Update build instructions for Mac

[BMW4673]

Attempted these new steps. QT5 certainly helped however still facing XCRUN
CMake Error at /usr/local/Cellar/cmake/3.19.7/share/cmake/Modules/CMakeTestCCompiler.cmake:66 (message):
The C compiler

"/usr/bin/cc"

is not able to compile a simple test program.

It fails with the following output:

Change Dir: /users/****/glabels-qt-master/CMakeFiles/CMakeTmp

Run Build Command(s):/usr/bin/make cmTC_e9010/fast && xcrun: error: invalid active developer path (/Library/Developer/CommandLineTools), missing xcrun at: /Library/Developer/CommandLineTools/usr/bin/xcrun

CMake will not be able to correctly generate this project.
Call Stack (most recent call first):
CMakeLists.txt:6 (project)

-- Configuring incomplete, errors occurred!
See also "/users//glabels-qt-master/CMakeFiles/CMakeOutput.log".
See also "/users/*****/glabels-qt-master/CMakeFiles/CMakeError.log".
brettwhitney@-MacBook glabels-qt-master % make
xcrun: error: invalid active developer path (/Library/Developer/CommandLineTools), missing xcrun at: /Library/Developer/CommandLineTools/usr/bin/xcrun
@-MacBook glabels-qt-master % sudo make install
Password:
xcrun: error: invalid active developer path (/Library/Developer/CommandLineTools), missing xcrun at: /Library/Developer/CommandLineTools/usr/bin/xcrun
@-MacBook glabels-qt-master %