20 minutes on an iMac with 3.4 GHz Core i7 processor and 16GB of main storage, with Sierra 10.12.6 and Qt 5.9.1 installed.
Note: There was no need for "make install", perhaps because I moved the initial unzipped folder to /Applications before starting the compilation process.
Mark
"make install" copies the files to the "correct" folder. if you don't do that, you alreays need to select the correct folder yourself. "make install" doesn't delete a compressed file.
You can speed up compiling by compiling on several threads/cpus by using "make -j4" (if you want to use 4 threads)