Add some stuff to README.md and configure Gitpod

.gitpod.yml

@@ -0,0 +1,20 @@
+# This configuration file was automatically generated by Gitpod.
+# Please adjust to your needs (see https://www.gitpod.io/docs/introduction/learn-gitpod/gitpod-yaml)
+# and commit this file to your remote git repository to share the goodness with others.
+
+# Learn more from ready-to-use templates: https://www.gitpod.io/docs/introduction/getting-started/quickstart
+
+tasks:
+  - before: |
+      sudo apt-get update
+      sudo DEBIAN_FRONTEND=noninteractive apt-get -y install cmake flex
+    init: |
+      make -C faust install PREFIX=$HOME/.local
+      make install
+      make all
+    command: |
+      make serve
+
+additionalRepositories:
+  - url: https://github.com/grame-cncm/faust.git
+    checkoutLocation: faustdoc/faust

README.md

@@ -6,8 +6,12 @@
 This repository is intended to build the documentation of the Faust environment, and to provide the corresponding examples. 
 
 ### Prerequisites
+- you must have make, "g++" (the GCC or Clang C++ driver), bison, and flex installed.
 - you must have python, pip and [mkdocs](https://www.mkdocs.org/) installed.
 - you must have the Faust source code installed. You can get it from [github](https://github.com/grame-cncm/faust). **Be sure to use a fresh cloned repository and to correcly install submodules with `git submodule update --init`**. The exact location can possibly be set in the make command using the `FAUSTDIR`  environment variable.
+- you must have Faust installed in PATH, too: it's used during the build.
+  [FIXME: does it need to be built in any particular way to get the right options in mkdocs/docs/manual/options.md?
+   Since that's checked in, this won't matter except when it actually needs to be updated.]
 - you must have openssl installed for base64 conversion.
 
 ###  WARNING: adding new files