Doc: add development setup documentation

DEVELOPMENT.md

@@ -0,0 +1,53 @@
+# GNURadio 4.0 Development Environment
+
+## Getting the source
+
+Get the source from the GitHub Repository:
+```bash
+git clone [email protected]:fair-acc/gnuradio4.git
+```
+
+## Building
+### Docker CLI
+To just compile GNURadio4 without installing any dependencies you can just use the Docker image which is also used by our CI builds. The snippet below uses `docker run` to start the container with the current directory mapped into the container with the correct user and group IDs.
+It then compiles the project and runs the testsuite.
+Note that while the binaries inside of `./build` can be accessed on the host system, they are linked against the libraries of the container and will most probably not run on the host system.
+
+```bash
+me@host$ cd gnuradio4
+me@host$ docker run \
+    --user `id -u`:`id -g` \
+    --volume="/etc/group:/etc/group:ro" \
+    --volume="/etc/passwd:/etc/passwd:ro" \
+    --volume="/etc/shadow:/etc/shadow:ro" \
+    --workdir=/build --volume `pwd`:/build  -it \
+    ghcr.io/fair-acc/gr4-build-container bash
+
+me@aba123ef$ # export CXX=c++ # uncomment to use clang
+me@aba123ef$ cmake -S . -B build
+me@aba123ef$ cmake --build build
+me@aba123ef$ cd build && ctest .
+```
+### Docker IDE
+Some IDEs provide a simple way to specify a docker container to use for building and executing a project. For example in JetBrains CLion you can set this up in `Settings->Build,Execution,Deployment->Toolchains->[+]->Docker`, leaving everything as the default except for setting `Image` to `ghcr.io/fair-acc/gr4-build-container`.
+By default this will use the gcc-14 compiler included in the image, by setting `CXX` to `clang++-18` you can also use clang.
+
+### Native
+To be able to natively compile some prerequisites have to be installed:
+- gcc >= 13 and/or clang >= 17
+- cmake >= 3.25.0
+- ninja (or GNU make)
+- optional for python block support: python3
+- optional for soapy (limesdr,rtlsdr) blocks: soapysdr
+- optional for compiling to webassembly: emscripten >= 3.1.50
+
+To apply the project's formatting rules, you'll also need the correct formatters, `clang-format-18` and `cmake-format`. With these installed you can use the scripts in the repository to reformat your changes. Otherwise 
+
+Once these are installed, you should be able to just compile and run GNURadio4:
+
+```bash
+me@host$ cd gnuradio4
+me@host$ cmake -S . -B build
+me@host$ cmake --build build
+me@host$ cd build && ctest .
+

README.md

@@ -22,6 +22,10 @@ led to adoption in hobbyist, academic, and commercial environments. GNU Radio ha
 found use in software-defined radio, digital communications, nuclear physics, high-
 energy particle physics, astrophysics, radio astronomy and more!
 
+## Development
+
+If you want to start working on the GNURadio 4.0 source, the [DEVELOPMENT.md](DEVELOPMENT.md) file describes how to set up a local development environment.
+
 ## Helpful Links
 
 * [GNU Radio Website](https://gnuradio.org)