Please add installation instructions

[stooby]

@jpcima @SpotlightKid
Hello, apologies if I'm missing something obvious, but after reading the README and user manual it's still unclear to me how to install faustpp for use with command line.

Would you be able to add some step-by-step installation instructions to the user manual please? I tried using CMake but am unsure if that's what you'd recommend using for installation.

I'm on macOS Big Sur 11.5.2, I have Faust 2.33.1 installed, I downloaded the latest faustpp code from the master branch, and tried installing it with Cmake 3.21.3, but it doesn't work.

First, I put the faustpp code in a directory on my system and ran the following with cmake from command line:
cmake --install /path/to/faustpp-master

...but then I get the following error:
"CMake Error: Error processing file: /path/to/faustpp-master/cmake_install.cmake"

Then I tried building the faustpp code with cmake from command line as follows:
cmake --build /path/to/faustpp-master

...but that didn't work either and resulted in the following error:
"Error: could not load cache"

Thanks in advance for your help clarifying the installation process. Sorry if it's something basic I'm overlooking. I'm new to working with more advanced post processing tools like this.

[SpotlightKid]

git clone --recursive https://github.com/jpcima/faustpp
cd faustpp
mkdir -p build && cd build
cmake -DCMAKE_BUILD_TYPE=Release -DCMAKE_INSTALL_PREFIX=/usr ..
make
make install

[SpotlightKid]

But note #9