Add mingw documentation

docs/README.md

@@ -21,6 +21,7 @@ Vcpkg helps you manage C and C++ libraries on Windows, Linux and MacOS. This too
 - [Binary Caching](users/binarycaching.md)
 - [Versioning](users/versioning.md)
 - [Usage with Android](users/android.md)
+- [Usage with MinGW](users/mingw.md)
 - [Host Dependencies](users/host-dependencies.md)
 
 ### Maintainer Help

docs/users/mingw.md

@@ -0,0 +1,101 @@
+# Vcpkg and MinGW
+
+**The latest version of this documentation is available on [GitHub](https://github.com/Microsoft/vcpkg/tree/master/docs/users/mingw.md).**
+
+## MinGW community triplets
+
+vcpkg includes
+[community triplets for MinGW](https://github.com/microsoft/vcpkg/tree/master/triplets/community)
+for x64, x86, arm64 and arm. They don't depend on Visual Studio and
+can be used natively on Windows as well as for cross-compiling on
+other operating systems. There are two variants of each triplet,
+selecting between static and dynamic linking:
+
+- arm64-mingw-dynamic
+- arm64-mingw-static
+- arm-mingw-dynamic
+- arm-mingw-static
+- x64-mingw-dynamic
+- x64-mingw-static
+- x86-mingw-dynamic
+- x86-mingw-static
+
+These triplets are not tested by continuous integration, so many ports
+do not build, and even existing ports may break on port updates.
+Because of this, community involvement is paramount!
+
+- [Discussions](https://github.com/microsoft/vcpkg/discussions?discussions_q=mingw)
+- [Open issues](https://github.com/microsoft/vcpkg/issues?q=is%3Aissue+is%3Aopen+mingw)
+- [Open pull requests](https://github.com/microsoft/vcpkg/pulls?q=is%3Apr+is%3Aopen+mingw)
+
+## Using MinGW natively on Windows
+
+With [MSYS2](https://www.msys2.org/), it is possible to easily create
+a full environment for building ports with MinGW on a Windows PC.
+
+Note that for building software for native windows environments, you
+must use a mingw subsystem of MSYS2, and install some packages 
+(with a specific prefix) for this subsystem.
+
+| architecture | vcpkg triplets                      | subsystem | package prefix    |
+|--------------|-------------------------------------|-----------|-------------------|
+| x64          | x64-mingw-dynamic, x64-mingw-static | mingw64   | mingw-w64-x86_64- |
+| x86          | x86-mingw-dynamic, x86-mingw-static | mingw32   | mingw-w64-i686-   |
+
+After the basic installation if MSYS2, you will need to install a few
+additional packages for software development, e.g. for x64:
+
+```bash
+pacman -S git mingw-w64-x86_64-cmake mingw-w64-x86_64-ninja
+```
+
+The active subsystem is select by running the MSYS2 MinGW app, or
+changed in a running terminal by
+
+```bash
+source shell mingw64   # or mingw32
+```
+
+The bootstrapping of vcpkg shall be done by running bootstrap_vcpkg.exe.
+This will download the official vcpkg.exe.
+
+```bash
+git clone https://github.com/microsoft/vcpkg.git
+cd vcpkg
+./bootstrap-vcpkg.bat
+```
+
+For building packages, you need to tell vcpkg that you want to use the
+MinGW triplet. This can be done in different ways. When Visual Studio
+is not installed, you must also set the host triplet to mingw. This is
+needed to resolve host dependencies. For convenience, you can use
+environment variables to set both triplets:
+
+```bash
+export VCPKG_DEFAULT_TRIPLET=x64-mingw-dynamic
+export VCPKG_DEFAULT_HOST_TRIPLET=x64-mingw-dynamic
+```
+
+Now you can test your setup:
+
+```bash
+./vcpkg install zlib
+```
+
+## Using MinGW to build Windows programs on other systems
+
+Many Linux distributions come with MinGW toolchains which allow to
+cross-compile software on Linux to be run on Windows. You can use
+such toolchains with vcpkg by setting the desired mingw triplet.
+
+Note that the pre-installed cmake might be too old for vcpkg.
+
+For bootstrapping, clone the github repository and run the shell script:
+
+```bash
+git clone https://github.com/microsoft/vcpkg.git
+cd vcpkg
+./bootstrap-vcpkg.sh
+./vcpkg install zlib:x64-mingw-dynamic
+```
+

docs/users/triplets.md

@@ -189,3 +189,6 @@ We recommend using a systematic naming scheme when creating new triplets. The An
 
 ## Android triplets
 See [android.md](android.md)
+
+## MinGW triplets
+See [mingw.md](mingw.md)