Document windows build prerequisite

INSTALL

@@ -1,13 +0,0 @@
-Build instructions for libcubeb
-===============================
-
-Note: If you are using MinGW, remove -pthread from src_libcubeb_la_LDFLAGS.
-
-Note Also:Cubeb does not currently build under Cygwin, but this is being worked on.
-
-0. Change directory into the source directory.
-1. Run |autoreconf --install| to generate configure.
-2. Run |./configure| to configure the build.
-3. Run |make| to build.
-4. Run |make check| to run the test suite.
-

INSTALL.md

@@ -0,0 +1,35 @@
+# Build instructions for libcubeb
+
+Note Also:Cubeb does not currently build under Cygwin, but this is being worked on.
+
+0. Change directory into the source directory.
+1. Run |autoreconf --install| to generate configure.
+2. Run |./configure| to configure the build.
+3. Run |make| to build.
+4. Run |make check| to run the test suite.
+
+# Debugging
+
+Debugging tests can be done like so:
+
+```libtool --mode=execute gdb test/test_tone```
+
+# Windows build prerequisite, using `msys2`
+
+Cubeb for Windows uses win32 threads
+
+- Download and install `msys2` 32-bits from <https://msys2.github.io>. Let it
+  install in `C:\msys32`.
+- Download and install `7z` from <http://www.7-zip.org/>.
+- Run `msys2` (a shortcut has been added to the start menu, or use the `.bat`
+  script: `C:\msys32\mingw32_shell.bat`), and issue the following commands to
+  install the dependencies:
+```pacman -S git automake autoconf libtool m4 make pkg-config gdb
+```
+- Download a `mingw` compiler with the WIN32 thread model [here](http://sourceforge.net/projects/mingw-w64/files/Toolchains%20targetting%20Win32/Personal%20Builds/mingw-builds/4.9.2/threads-win32/sjlj/i686-4.9.2-release-win32-sjlj-rt_v3-rev0.7z/download). `msys2` does not have `mingw` builds with win32 threads,
+so we have to install another compiler.
+- Unzip the compiler, and copy all folders in `C:\msys32\opt`
+- Exit the `msys2` shell, and run `C:\msys32\autorebase.bat` (double clicking
+  works).
+- Open an `msys2` shell and follow the build instructions.
+