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       MinGW/MSYS Installation Instructions for LLVM and Pure Compilation
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MinGW is a Windows port of the GNU compiler suite which produces native
executables on the Windows platform (see http://www.mingw.org).

MSYS is a small system which enables to run GNU utilities and shell scripts
on Windows, namely the configure scripts and GNU make (see
http://www.mingw.org/msys.shtml).

Here you find instructions how to install both these packages in order to
successfully compile LLVM and Pure on your Windows box.

Both MinGW and MSYS can be downloaded from this page:
http://sourceforge.net/project/showfiles.php?group_id=2435

1. MinGW Installation

   Download the latest MinGW installation program ("MinGW-5.1.4.exe" in my
   case) and binutils 2.18.50 ("binutils-2.18.50-20080109-2.tar.gz").

   Launch the installation program, when asked check "Download and Install" and
   when again asked select "Current" package to be installed. On the next
   dialog window you can select packages to be installed. Select at least
   "MinGW base tools" and "g++ compiler". You can select other stuff if you
   plan to use it. DO NOT select "MinGW Make", it is very defficient. In the
   next dialog box select a suitable installation folder e.g. "d:\mingw" in my
   case, and proceed.
   
   In the next step install the newer version of binutils. Simply extract the
   tree from the gzipped tarball over the MinGW installation tree (i.e. from
   bin/ to bin/ etc.) and allow files to be overwritten.

2. MSYS installation

   From the page mentioned above download the following packages:
   - current release of MSYS-xxx.exe ("MSYS-1.0.10.exe" in my case)
   - current release of msysDTK-yyy.exe ("msysDTK-1.0.1.exe")
   - latest version of bison ("bison-2.3-MSYS-1.0.11-1.tar.bz2")
   - latest version of flex ("flex-2.5.33-MSYS-1.0.11-1.tar.bz2")
   - latest version of regex ("regex-0.12-MSYS-1.0.11-1.tar.bz2")

   Launch the MSYS installation program and install MSYS into a DIFFERENT
   folder than MinGW (e.g. "D:\msys\1.0" in my case). Then proceed further.
   Reply "y" when asked whether to continue with postinstall, "y" when asked
   whether MinGW is intalled and type the path to your MinGW installation when
   asked to do so. Use normal slashes in that path (e.g. "d:/mingw"). Should
   this setp fail then edit the file ".../msys/1.0/etc/fstab" so that it
   contains the line ".../MinGW /mingw" (e.g. "d:/MinGW /mingw" in my case).

   Launch the msysDTK installation program and install msysDTK into the SAME
   folder as MSYS (e.g. "D:\msys\1.0" in my case).

   In the next step install bison and flex. Simply extract the trees from
   the bzipped tarballs over the MSYS installation tree (i.e. from bin/
   to bin/ etc.).

   From the regex package copy only the file "/bin/msys-regex-0.dll" to
   msys/1.0/bin.

   DO NOT copy anything else into the MSYS tree unless you know what you are
   doing.
 
3. Installation of other necessary packages

   Download the package "http://pure-lang.sourceforge.net/mingw/pure-mingw.zip"
   prepared by Albert Graef. Then create a folder ".../MinGW/local" in your
   MinGW tree and unpack the tree from the pure-mingw.zip into that
   folder.

   Continue creating a folder "...msys/1.0/etc/profile.d" in your MSYS tree.
   Using your preferred text editor create a new text file named "local.sh"
   and paste the following four lines (including double quotes) into it:

export PATH=.:/d/MinGW/local/bin:/d/MinGW/bin:$PATH
export LIBRARY_PATH="d:\mingw\local\lib;d:\mingw\lib"
export C_INCLUDE_PATH="d:\mingw\local\include;d:\mingw\include"
export CPLUS_INCLUDE_PATH="D:\MinGW\local\include;D:\MinGW\include\c++\3.4.5;D:\MinGW\include\c++\3.4.5\backward;D:\MinGW\include\c++\mingw32;D:\MinGW\include"

   Then update the paths to real location of your MinGW tree and save the file.
   When a new shell is started, all shell scripts from the ".../etc/profile.d"
   folder are executed. This way we needn't to modify the profile file itself.

   Your MinGW/MSYS environment should be now prepared to compile LLVM and Pure.

4. LLVM compilation

   Here you can follow the INSTALL file with two exceptions:
   
   - You need to apply the patch "DynamicLibrary.inc.patch" to the file
     ".../llvm-2.2/lib/System/Win32/DynamicLibrary.inc". Download the
     patchfile from http://pure-lang.sf.net/mingw/ and save it to the
     ".../llvm-2.2" folder. Then cd in the MSYS shell to that folder and
     type "patch lib/System/Win32/DynamicLibrary.inc DynamicLibrary.inc.patch".

   - We did not install groff and perldoc packages so that LLVM doc files
     cannot be generated and installed. To install LLVM use the command
     "make -k install" and it will continue over the complaints about
     missing those two packages.