3. Using a shadow directory of symbolic links for the build

A recommended practice is to use a shadow directory of symbolic links to do the build of XFree86. This permits to keep the source directory unmodified during the build, which has the following benefits:

• In the case where CVS is used to maintain the source tree up to date, the update process is not disturbed by foreign files not under the control of CVS.
• It is possible to build XFree86 for several different Operating System or architectures from the same sources, shared by read-only NFS mounts.
• It is possible to build XFree86 with different configuration options, just by putting a real copy of the host.def file in each build tree and by customizing it separately in each build tree.

To make a shadow directory of symbolic links, use the following steps:

• create the directory at the top of the build tree. It is often created at the same level that the xc directory, but this is not mandatory.

  cd the directory containing the xcdirectory
mkdir build

• use the "lndir" command to make the shadow tree:

  lndir ../xc

  Note that you can refer to the xc directory with an absolute path if needed.

  See the lndir(1) manual page for details.

cd xc/config/util
make -f Makefile.ini lndir
cp lndir some directory in your PATH

From time to time there may be some stale links in the build tree, for example, when files in the source tree are removed or renamed. These can be cleaned up by running the "cleanlinks" script from the build directory (see the cleanlinks(1) manual page). Rarely there will be changes that will require the build tree to be re-created from scratch. A symptom of this can be mysterious build problems. The best solution for this is to remove the build tree, and then re-create it using the steps outlined above.