Updated Linux section of README.md

1 files changed, 29 insertions, 7 deletions

diff --git a/README.md b/README.md
index 57e43b62e..288776636 100644
--- a/README.md
+++ b/README.md
@@ -57,14 +57,35 @@ Binaries are located in the `build` directory
 
 The following instructions have been collated using Ubuntu 20.04.
 
-At the time of writing only GCC v11 supports the C++20 features used by Zen. As
-this version is not available in the default package repositories we need to
-get GCC from one of Ubuntu's toolchain repositories;
+Zen makes heavy use of C++20 features which at the time of writing has limited
+toolchain and C++ library support. A minimum compiler version of GCC-11 or
+Clang-12 is required, along with GNU's libstdc+++-11 or newer. Note that it is
+not currently possible to use anything other than the system's default C++
+library (e.g. LLVM's libc++) due to the way that Zen's third party dependencies
+are managed via `vcpkg`.
+
+The first step is to acquire a suitable compiler and C++ library. On Ubuntu 20.04
+GCC-11 is not available in the standard package repositories so Ubuntu's tool-
+chain test respository needs to be added to Apt (note that this is _not required_
+for Ubuntu 21.04 onwards);
 
 ```
 sudo add-apt-repository -y ppa:ubuntu-toolchain-r/test
-sudo apt install -y gcc-11
-gcc-11 --version
+```
+
+Now GCC-11 can be install via Apt. This will also install a suitable version of
+the C++ library too;
+
+```
+sudo apt install -y --no-install-recommends g++-11
+g++-11 --version
+```
+
+The easiest way to tell `xmake` to use the correct compiler version is to set
+the `CXX` environment variable;
+
+```
+export CXX=g++-11
 ```
 
 Next we need the `xmake` build system. For this we will download and install
@@ -72,17 +93,18 @@ Next we need the `xmake` build system. For this we will download and install
 date `.deb` files;
 
 ```
-wget https://github.com/xmake-io/xmake/releases/download/v2.5.7/xmake-v2.5.7.amd64.deb
+wget https://github.com/xmake-io/xmake/releases/download/v2.6.2/xmake-v2.6.2.amd64.deb
 sudo dpkg -i xmake-v2.5.7.amd64.deb
 xmake --version
 ```
 
 For some of Zen's third party dependencies are provided by Microsoft's `vcpkg`
-C++ library manager. After cloning the project there is a initialisation step;
+C++ library manager. After cloning the project there is an initialisation step;
 
 ```
 git clone https://github.com/microsoft/vcpkg.git ~/zen/vcpkg
 ~/zen/vcpkg/bootstrap-vcpkg.sh
+~/zen/vcpkg/vcpkg --version
 ```
 
 `xmake` uses an environment variable to find `vcpkg`. Alternatively this can be