Enable using the Ninja generator instead of Visual Studio on Windows builds.

docs/workflow/requirements/freebsd-requirements.md

@@ -57,11 +57,12 @@ Install the following packages:
 - lttng-ust
 - krb5
 - openssl (optional)
+- ninja (optional, enables building native code with ninja instead of make)
 
 The lines to install all the packages above using package manager.
 
 ```sh
-sudo pkg install --yes libunwind icu libinotify lttng-ust krb5 cmake autoconf automake openssl
+sudo pkg install --yes libunwind icu libinotify lttng-ust krb5 cmake autoconf automake openssl ninja
 ```
 
 Additionally, working dotnet cli with SDK is needed. On other platforms this would be downloaded automatically during build but it is not currently available for FreeBSD.

docs/workflow/requirements/linux-requirements.md

@@ -50,6 +50,7 @@ Install the following packages for the toolchain:
 - libkrb5-dev
 - libnuma-dev (optional, enables numa support)
 - zlib1g-dev
+- ninja (optional, enables building native code with ninja instead of make)
 
 The following dependencies are needed if Mono Runtime is enabled (default behavior):
 
@@ -61,7 +62,7 @@ The following dependencies are needed if Mono Runtime is enabled (default behavi
 sudo apt-get install -y cmake llvm-9 clang-9 autoconf automake \
 libtool build-essential python curl git lldb-6.0 liblldb-6.0-dev \
 libunwind8 libunwind8-dev gettext libicu-dev liblttng-ust-dev \
-libssl-dev libnuma-dev libkrb5-dev zlib1g-dev
+libssl-dev libnuma-dev libkrb5-dev zlib1g-dev ninja
 ```
 
 You now have all the required components.

docs/workflow/requirements/macos-requirements.md

@@ -28,8 +28,9 @@ Install the following packages:
 - openssl 1.1
 - pkg-config
 - python3
+- ninja (optional, enables building native code with ninja instead of make)
 
-You can install all the packages above using Homebrew by running this command in the repository root:
+You can install all the required packages above using Homebrew by running this command in the repository root:
 
 ```
 brew bundle --no-lock --file eng/Brewfile

docs/workflow/requirements/windows-requirements.md

@@ -42,7 +42,13 @@ The dotnet/runtime repository requires at least Visual Studio 2019 16.6.
 - Add its location (e.g. C:\Program Files (x86)\CMake\bin) to the PATH environment variable.
   The installation script has a check box to do this, but you can do it yourself after the fact following the instructions at [Adding to the Default PATH variable](#adding-to-the-default-path-variable).
 
-The dotnet/runtime repository requires at least CMake 3.15.5.
+The dotnet/runtime repository recommends using CMake 3.16.0 or newer, but works with CMake 3.15.5.
+
+## Ninja (optional)
+
+- Install Ninja in one of the two following ways
+  - [Download the executable](https://github.com/ninja-build/ninja/releases) and add it's location to [the Default PATH variable](#adding-to-the-default-path-variable).
+  - [Install via a package manager](https://github.com/ninja-build/ninja/wiki/Pre-built-Ninja-packages), which should automatically add it to the PATH environment variable.
 
 ## Python
 

eng/native/set-cmake-path.ps1

@@ -64,7 +64,10 @@ try {
   $version = [Version]$(& $cmakePath --version | Select-String -Pattern '\d+\.\d+\.\d+' | %{$_.Matches.Value})
 
   if ($version -lt [Version]"3.14.0") {
-      Throw "This repository requires CMake 3.14. The newest version of CMake installed is $version. Please install CMake 3.14 or newer from https://cmake.org/download/ and ensure it is on your path."
+      Throw "This repository requires CMake 3.14 and recommends CMake 3.16. The newest version of CMake installed is $version. Please install CMake 3.16 or newer from https://cmake.org/download/ and ensure it is on your path."
+  }
+  elseif ($version -lt [Version]"3.16.0") {
+    [System.Console]::Error.WriteLine("CMake 3.16 or newer is recommended for building this repository. The newest version of CMake installed is $version. Please install CMake 3.16 or newer from https://cmake.org/download/ and ensure it is on your path.")
   }
 
   [System.Console]::WriteLine("set CMakePath=" + $cmakePath)