DOC: Document Carl Kleffner's MinGW-w64 toolchain in INSTALL.txt.

Taken from the description in gh-5587.

1 files changed, 32 insertions, 0 deletions

diff --git a/INSTALL.txt b/INSTALL.txt
index 01726df04..7a0a57ee5 100644
--- a/INSTALL.txt
+++ b/INSTALL.txt
@@ -130,6 +130,38 @@ is broken). gcc 4.4 will hopefully be able to run natively.
 This is the only tested way to get a numpy with a FULL blas/lapack (scipy
 does not work because of C++).
 
+Carl Kleffner's mingw-w64 toolchain
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Carl Kleffner has been working on mingw-w64 / OpenBLAS support and has put
+together toolchains for that option. The toolchains are available at 
+https://bitbucket.org/carlkl/mingw-w64-for-python/downloads. The site.cfg
+should be configured like so:
+
+[openblas]
+libraries = openblaspy
+library_dirs = <openblaspath>/lib
+include_dirs = <openblaspath>/include
+
+The libopenblaspy.dll from <openblaspath>/bin must be copied to numpy/core
+before the build. For this mingw-w64 toolchain manual creation of the python
+import libs is necessary, i.e.:
+
+gendef python2.7.dll
+dlltool -D python27.dll -d python27.def -l libpython27.dll.a
+move libpython27.dll.a libs\libpython27.dll.a
+
+For python-2.6 up to python 3.2 use
+https://bitbucket.org/carlkl/mingw-w64-for-python/downloads/mingwpy_win32_vc90.tar.xz
+or
+https://bitbucket.org/carlkl/mingw-w64-for-python/downloads/mingwpy_amd64_vc90.tar.xz
+
+For python-3.3 and python-3.4 use
+https://bitbucket.org/carlkl/mingw-w64-for-python/downloads/mingwpy_win32_vc100.tar.xz
+or
+https://bitbucket.org/carlkl/mingw-w64-for-python/downloads/mingwpy_amd64_vc100.tar.xz
+ 
+
 MS compilers
 ------------