Additional information for landing page

Author: jokalode

README.md

@@ -1,3 +1,43 @@
 [![C++ build](https://github.com/glvi/cbor_cpp/actions/workflows/cpp.yaml/badge.svg)](https://github.com/glvi/cbor_cpp/actions/workflows/cpp.yaml)
 # cbor_cpp
 C++ utilities for decoding Concise Binary Object Representation
+
+## Tested on
+
+- macOS 26
+- macOS 15.5
+- ubuntu 24.04
+
+## Dependencies
+
+### Requires
+
+- A C++ compiler supporting C++23
+- [GNU Autoconf](https://www.gnu.org/software/autoconf)
+- [GNU Automake](https://www.gnu.org/software/automake)
+- [GNU Autogen](https://www.gnu.org/software/autogen)
+- [GNU Libtool](https://www.gnu.org/software/libtool)
+- [DejaGnu](https://www.gnu.org/software/dejagnu)
+
+## Check out
+```sh
+git clone https://github.com/glvi/cbor_cpp
+```
+
+## Build from source
+```sh
+autoreconf -fis
+mkdir -p build
+(cd build && ../configure CXXFLAGS=-std=c++23 CPPFLAGS=-I/usr/local/include)
+gmake -j -C build check
+```
+
+You can choose any other name for the `build` directory.
+
+Modify `CXXFLAGS` accordingly, if your compiler uses a different
+directive to support C++23, or if you want to specify additional
+compiler flags.
+
+Modify `CPPFLAGS` accordingly, if your installation of DejaGnu resides
+in a different location, or if you want to specify additional
+preprocessor flags.