Improve docs on windows building

1 files changed, 35 insertions, 39 deletions

diff --git a/INSTALL.md b/INSTALL.md
index 686145566f..24f088ea49 100644
--- a/INSTALL.md
+++ b/INSTALL.md
@@ -61,49 +61,45 @@ gRPC C Core library.
 There are several ways to build under Windows, of varying complexity depending
 on experience with the tools involved.
 
-<!--
-###Visual Studio
+###Pre-generated Visual Studio solution
 
-Versions 2013 and 2015 are both supported. You can use [their respective
-community
-editions](https://www.visualstudio.com/en-us/downloads/download-visual-studio-vs.aspx).
-
-Building the C Core:
-- Open [grpc.sln](https://github.com/grpc/grpc/blob/master/vsprojects/grpc.sln).
-- Select your build target.
-- Build the `grpc` project.
+The pre-generated VS projects & solution are checked into the repository under the [vsprojects](/vsprojects) directory.
+  
+###Building using CMake (with BoringSSL)
+- Install [CMake](https://cmake.org/download/).
+- Install [Active State Perl](http://www.activestate.com/activeperl/) (`choco install activeperl`)
+- Install [Ninja](https://ninja-build.org/) (`choco install ninja`)
+- Install [Go](https://golang.org/dl/) (`choco install golang`)
+- Install [yasm](http://yasm.tortall.net/) and add it to `PATH` (`choco install yasm`)
+- Run these commands in the repo root directory
+```
+> md .build
+> cd .build
+> call "%VS140COMNTOOLS%..\..\VC\vcvarsall.bat" x64
+> cmake .. -GNinja -DCMAKE_BUILD_TYPE=Release
+> cmake --build .
+```
+NOTE: Currently you can only use Ninja to build using cmake on Windows (because of the boringssl dependency).
 
-Building the C++ runtime:
-- You need [CMake](https://cmake.org/) on your path to build protobuf (see below
-  for building using solely CMake).
-- Run `vsprojects/build_protos.bat` (needs `cmake.exe` in your path).
-- Open [buildtests_cxx.sln]()
-- Select your build target.
-- build the `grpc++` project.
--->
+###msys2 (with mingw)
 
-###msys2
+The Makefile (and source code) should support msys2's mingw32 and mingw64
+compilers. Building with msys2's native compiler is also possible, but
+difficult.
 
 This approach requires having [msys2](https://msys2.github.io/) installed.
+  
+```
+# Install prerequisites
+MSYS2$ pacman -S autoconf automake gcc libtool mingw-w64-x86_64-toolchain perl pkg-config zlib
+MSYS2$ pacman -S mingw-w64-x86_64-gflags
+```
 
-- The Makefile (and source code) should support msys2's mingw32 and mingw64
-  compilers. Building with msys2's native compiler is also possible, but
-  difficult.
-- The Makefile is expecting the Windows versions of OpenSSL (see
-  https://slproweb.com/products/Win32OpenSSL.html). It's also possible to build
-  the Windows version of OpenSSL from scratch. The output should be `libeay32`
-  and `ssleay32`.
-- If you are not installing the above files under msys2's path, you may specify
-  it, for instance, in the following way:
-  ```CPPFLAGS=”-I/c/OpenSSL-Win32/include” LDFLAGS=”-L/c/OpenSSL-Win32/lib” make static_c```
-- [protobuf3](https://github.com/google/protobuf/blob/master/src/README.md#c-installation---windows)
-  must be installed on the msys2 path.
-
-###Cmake (experimental)
+```
+# From mingw shell
+MINGW64$ export CPPFLAGS="-D_WIN32_WINNT=0x0600"
+MINGW64$ make
+```
 
-- Install [CMake](https://cmake.org/download/).
-- Run it over [grpc's
-  CMakeLists.txt](https://github.com/grpc/grpc/blob/master/CMakeLists.txt) to
-  generate "projects" for your compiler.
-- Build with your compiler of choice. The generated build files should have the
-  protobuf3 dependency baked in.
+NOTE: While most of the make targets are buildable under Mingw, some haven't been ported to Windows yet
+and may fail to build (mostly trying to include POSIX headers not available on Mingw).