\chapter{Building darcs}

This chapter should walk you through the steps necessary to build darcs for
yourself.  There are in general two ways to build darcs.  One is for
building released versions from tarballs, and the other is to build the
latest and greatest darcs, from the darcs repo itself.

Please let me know if you have any problems building darcs, or don't have
problems described in this chapter and think there's something obsolete
here, so I can keep this page up-to-date.

\section{Prerequisites}
To build darcs you will need to have {\tt ghc}, the Glorious Glasgow
Haskell Compiler. You should have at the very minimum version 6.2.

It is a good idea (but not required) to have a recent version of libcurl
installed.  If not, you will at least need to have either {\tt wget} or
{\tt curl} installed if you want to be able to grab repos remotely over
normal network protocols (ftp or http).  You also might want to have scp
available if you want to grab your repos over ssh\ldots

To send patches, you will also need to have a working
\verb!/usr/sbin/sendmail! or \verb!/usr/lib/sendmail!, which is provided
by most mail transport agents, and is generally available on linux and
BSD systems.  It's also there on Mac~OS~X. However, if you don't have this,
it won't stop you from building darcs.

To use the \verb!diff! command of darcs, a \verb!diff! program supporting
options \verb!-r! (recursive diff) and \verb!-N! (show new files as
differences against an empty file) is required. The \verb!configure!
script will look for \verb!gdiff!, \verb!gnudiff! and \verb!diff! in this
order. You can force the use of another program by setting the \verb!DIFF!
environment variable before running \verb!configure!.

To rebuild the documentation (which should not be necessary since it is
included in html form with the tarballs), you will need to have latex
installed, as well as latex2html if you want to build it in html form.

\section{Building on Mac~OS~X}
To build on Mac~OS~X, you will need the Apple Developer Tools and the ghc
6.4 package installed.

\section{Building on Microsoft Windows}
To build on Microsoft Windows, you will need:

\begin{itemize}
\item \htmladdnormallinkfoot{MinGW}{http://www.mingw.org/} which provides the GCC
  toolchain for win32.
\item \htmladdnormallinkfoot{MSYS}{http://www.mingw.org/msys.shtml} which provides
  a unix build environment for win32.  Be sure to download the separate
  msysDTK, autoconf and automake.
\item \htmladdnormallinkfoot{zlib-1.2.1+}{http://www.gzip.org/zlib/} library
  and headers.
\item \htmladdnormallinkfoot{curl-7.12.2+}{http://curl.haxx.se/} library
  and headers.
\item If building with an SSL enabled curl you will need the OpenSSL
  libraries, unofficial builds are available at\\
  \htmladdnormallink{http://www.slproweb.com/products/Win32OpenSSL.html}{http://www.slproweb.com/products/Win32OpenSSL.html}.
\end{itemize}

Copy the zlib and curl libraries and headers to both GHC and MinGW.  GHC
stores C headers in \verb!<ghc-dir>/gcc-lib/include! and libraries in
\verb!<ghc-dir>/gcc-lib!.  MinGW stores headers in
\verb!<mingw-dir>/include! and libraries in \verb!<mingw-dir>/lib!.

Set PATH to include the \verb!<msys-dir>/bin!, \verb!<mingw-dir>/bin!,
\verb!<curl-dir>!, and a directory containing a pre-built darcs.exe if you
want the build's patch context stored for `\verb!darcs --exact-version!'.

\begin{verbatim}
C:\darcs> cd <darcs-source-dir>
C:\darcs> sh

$ export GHC=/c/<ghc-dir>/bin/ghc.exe
$ autoconf
$ ./configure --disable-mmap --target=mingw
$ make
\end{verbatim}

\section{Building from tarball}
If you get darcs from a tarball, the procedure (after unpacking the tarball
itself) is as follows:
\begin{verbatim}
% ./configure
% make
# Optional, but recommended
% make test
% make install
\end{verbatim}

There are options to configure that you may want to check out with
\begin{verbatim}
% ./configure --help
\end{verbatim}

If your header files are installed in a non-standard location, you may need
to define the \verb!CFLAGS! and \verb!CPPFLAGS! environment variables to
include the path to the headers.  e.g. on NetBSD, you may need to run
\begin{verbatim}
% CFLAGS=-I/usr/pkg/include CPPFLAGS=-I/usr/pkg/include ./configure
\end{verbatim}

\section{Building darcs from the repository}
To build the latest darcs from its repository, you will first need a
working copy of darcs. You can get darcs using:
\begin{verbatim}
% darcs get -v http://abridgegame.org/repos/darcs
\end{verbatim}
and once you have the darcs repository you can bring it up to date with a
\begin{verbatim}
% darcs pull
\end{verbatim}

The repository doesn't hold automatically generated files, which include
the configure script and the HTML documentation, so you need to run
\verb!autoconf! first. 

You'll need \verb!autoconf! 2.50 or higher. Some systems have more than one
version of \verb!autoconf! installed. For example, \verb!autoconf! may point to
version 2.13, while \verb!autoconf259!  runs version 2.59. 

Also note that \verb!make! is really "GNU make". On some systems, such as
the *BSDs, you may need to type \verb!gmake! instead of make for this to work.

If you want to create readable documentation you'll need to have latex installed.
\begin{verbatim}
% autoconf
% ./configure
% make
% make install
\end{verbatim}

If you want to tweak the configure options, you'll need to run {\tt
  ./configure} yourself after the make, and then run make again.

\section{Building darcs with git}

To enable git support, you first need to grab a copy of the git
source code; since darcs doesn't yet have the capability of accessing
remote git repositories, you'll have to either download a tarball or use
git itself to clone a git repository.  Compile git (no need to
install); this will create a file ``\verb|libgit.a|''.  Then create a
symlink to the git source directory named ``\verb!git!'' in your darcs
source directory, configure darcs using the ``\verb!--enable-git!''
option, and build darcs as usual.

\section{Submitting patches to darcs}
I know, this doesn't really belong in this chapter, but if you're using the
repository version of darcs it's really easy to submit patches to me using
darcs. In fact, even if you don't know any Haskell, you could submit fixes
or additions to this document (by editing \verb!building_darcs.tex!) based
on your experience building darcs\ldots

To do so, just record your changes (which you made in the darcs repository)
\begin{verbatim}
% darcs record --no-test
\end{verbatim}
making sure to give the patch a nice descriptive name.  The
\verb!--no-test! options keeps darcs from trying to run the unit tests,
which can be rather time-consuming.  Then you can send the patch to the
darcs-devel mailing list by email by
\begin{verbatim}
% darcs send -u
\end{verbatim}
The darcs repository stores the email address to which patches should be
sent by default.  The email address you see is actually my own, but when
darcs notices that you haven't signed the patch with my GPG key, it will
forward the message to darcs-devel.

