INSTALL

Installation Instructions
*************************

Copying and distribution of this file, with or without modification, are permitted in any
medium without royalty provided the copyright notice and this notice are preserved.  This
file is offered as-is, without warranty of any kind.

Basic Installation
==================

Briefly, the shell commands `./configure; make; make install' should configure, build, and
install this package.  The following more-detailed instructions are generic; see the
`README' file for instructions specific to this package.  Some packages provide this
`INSTALL' file but do not implement all of the features documented below.  The lack of an
optional feature in a given package is not necessarily a bug.  More recommendations for
GNU packages can be found in *note Makefile Conventions: (standards)Makefile Conventions.

The `configure' shell script attempts to guess correct values for various system-dependent
variables used during compilation.  It uses those values to create a `Makefile' in each
directory of the package.  It may also create one or more `.h' files containing
system-dependent definitions.  Finally, it creates a shell script `config.status' that you
can run in the future to recreate the current configuration, and a file `config.log'
containing compiler output (useful mainly for debugging `configure').

It can also use an optional file (typically called `config.cache' and enabled with
`--cache-file=config.cache' or simply `-C') that saves the results of its tests to speed
up reconfiguring.  Caching is disabled by default to prevent problems with accidental use
of stale cache files.

If you need to do unusual things to compile the package, please try to figure out how
`configure' could check whether to do them, and mail diffs or instructions to the address
given in the `README' so they can be considered for the next release.  If you are using
the cache, and at some point `config.cache' contains results you don't want to keep, you
may remove or edit it.

The file `configure.ac' (or `configure.in') is used to create `configure' by a program
called `autoconf'.  You need `configure.ac' if you want to change it or regenerate
`configure' using a newer version of `autoconf'.

The simplest way to compile this package is:

  1. `cd' to the directory containing the package's source code and type `./configure' to
     configure the package for your system.

     Running `configure' might take a while.  While running, it prints some messages
     telling which features it is checking for.

  2. Type `make' to compile the package.

  3. Optionally, type `make check' to run any self-tests that come with the package,
     generally using the just-built uninstalled binaries.

  4. Type `make install' to install the programs and any data files and documentation.
     When installing into a prefix owned by root, it is recommended that the package be
     configured and built as a regular user, and only the `make install' phase executed
     with root privileges.

  5. Optionally, type `make installcheck' to repeat any self-tests, but this time using
     the binaries in their final installed location.  This target does not install
     anything.  Running this target as a regular user, particularly if the prior `make
     install' required root privileges, verifies that the installation completed
     correctly.

  6. You can remove the program binaries and object files from the source code directory
     by typing `make clean'.  To also remove the files that `configure' created (so you
     can compile the package for a different kind of computer), type `make distclean'.
     There is also a `make maintainer-clean' target, but that is intended mainly for the
     package's developers.  If you use it, you may have to get all sorts of other programs
     in order to regenerate files that came with the distribution.

  7. Often, you can also type `make uninstall' to remove the installed files again.  In
     practice, not all packages have tested that uninstallation works correctly, even
     though it is required by the GNU Coding Standards.

  8. Some packages, particularly those that use Automake, provide `make distcheck', which
     can by used by developers to test that all other targets like `make install' and
     `make uninstall' work correctly.  This target is generally not run by end users.

Compilers and Options
=====================

Some systems require unusual options for compilation or linking that the `configure'
script does not know about.  Run `./configure --help' for details on some of the pertinent
environment variables.

Compiling For Multiple Architectures
====================================

You can compile the package for more than one kind of computer at the same time, by
placing the object files for each architecture in their own directory.  To do this, you
can use GNU `make'.  `cd' to the directory where you want the object files and executables
to go and run the `configure' script.  `configure' automatically checks for the source
code in the directory that `configure' is in and in `..'.  This is known as a "VPATH"
build.

With a non-GNU `make', it is safer to compile the package for one architecture at a time
in the source code directory.  After you have installed the package for one architecture,
use `make distclean' before reconfiguring for another architecture.

On MacOS X 10.5 and later systems, you can create libraries and executables that work on
multiple system types--known as "fat" or "universal" binaries--by specifying multiple
`-arch' options to the compiler but only a single `-arch' option to the preprocessor.
Like this:

     ./configure CC="gcc -arch i386 -arch x86_64 -arch ppc -arch ppc64" \
                 CXX="g++ -arch i386 -arch x86_64 -arch ppc -arch ppc64" \
                 CPP="gcc -E" CXXCPP="g++ -E"

This is not guaranteed to produce working output in all cases, you may have to build one
architecture at a time and combine the results using the `lipo' tool if you have problems.

Installation Names
==================

By default, `make install' installs the package's commands under `/usr/local/bin', include
files under `/usr/local/include', etc.  You can specify an installation prefix other than
`/usr/local' by giving `configure' the option `--prefix=PREFIX', where PREFIX must be an
absolute file name.

You can specify separate installation prefixes for architecture-specific files and
architecture-independent files.  If you pass the option `--exec-prefix=PREFIX' to
`configure', the package uses PREFIX as the prefix for installing programs and libraries.
Documentation and other data files still use the regular prefix.

In addition, if you use an unusual directory layout you can give options like
`--bindir=DIR' to specify different values for particular kinds of files.  Run `configure
--help' for a list of the directories you can set and what kinds of files go in them.  In
general, the default for these options is expressed in terms of `${prefix}', so that
specifying just `--prefix' will affect all of the other directory specifications that were
not explicitly provided.

The most portable way to affect installation locations is to pass the correct locations to
`configure'; however, many packages provide one or both of the following shortcuts of
passing variable assignments to the `make install' command line to change installation
locations without having to reconfigure or recompile.

The first method involves providing an override variable for each affected directory.  For
example, `make install prefix=/alternate/directory' will choose an alternate location for
all directory configuration variables that were expressed in terms of `${prefix}'.  Any
directories that were specified during `configure', but not in terms of `${prefix}', must
each be overridden at install time for the entire installation to be relocated.  The
approach of makefile variable overrides for each directory variable is required by the GNU
Coding Standards, and ideally causes no recompilation.  However, some platforms have known
limitations with the semantics of shared libraries that end up requiring recompilation
when using this method, particularly noticeable in packages that use GNU Libtool.

The second method involves providing the `DESTDIR' variable.  For example, `make install
DESTDIR=/alternate/directory' will prepend `/alternate/directory' before all installation
names.  The approach of `DESTDIR' overrides is not required by the GNU Coding Standards,
and does not work on platforms that have drive letters.  On the other hand, it does better
at avoiding recompilation issues, and works well even when some directory options were not
specified in terms of `${prefix}' at `configure' time.

Optional Features
=================

If the package supports it, you can cause programs to be installed with an extra prefix or
suffix on their names by giving `configure' the option `--program-prefix=PREFIX' or
`--program-suffix=SUFFIX'.

Some packages pay attention to `--enable-FEATURE' options to `configure', where FEATURE
indicates an optional part of the package.  They may also pay attention to
`--with-PACKAGE' options, where PACKAGE is something like `gnu-as' or `x' (for the X
Window System).  The `README' should mention any `--enable-' and `--with-' options that
the package recognizes.

For packages that use the X Window System, `configure' can usually find the X include and
library files automatically, but if it doesn't, you can use the `configure' options
`--x-includes=DIR' and `--x-libraries=DIR' to specify their locations.

Some packages offer the ability to configure how verbose the execution of `make' will be.
For these packages, running `./configure --enable-silent-rules' sets the default to
minimal output, which can be overridden with `make V=1'; while running `./configure
--disable-silent-rules' sets the default to verbose, which can be overridden with `make
V=0'.

Specifying the System Type
==========================

There may be some features `configure' cannot figure out automatically, but needs to
determine by the type of machine the package will run on.  Usually, assuming the package
is built to be run on the _same_ architectures, `configure' can figure that out, but if it
prints a message saying it cannot guess the machine type, give it the `--build=TYPE'
option.  TYPE can either be a short name for the system type, such as `sun4', or a
canonical name which has the form:

     CPU-COMPANY-SYSTEM

where SYSTEM can have one of these forms:

     OS
     KERNEL-OS

See the file `config.sub' for the possible values of each field.  If `config.sub' isn't
included in this package, then this package doesn't need to know the machine type.

If you are _building_ compiler tools for cross-compiling, you should use the option
`--target=TYPE' to select the type of system they will produce code for.

If you want to _use_ a cross compiler, that generates code for a platform different from
the build platform, you should specify the "host" platform (i.e., that on which the
generated programs will eventually be run) with `--host=TYPE'.

Sharing Defaults
================

If you want to set default values for `configure' scripts to share, you can create a site
shell script called `config.site' that gives default values for variables like `CC',
`cache_file', and `prefix'.  `configure' looks for `PREFIX/share/config.site' if it
exists, then `PREFIX/etc/config.site' if it exists.  Or, you can set the `CONFIG_SITE'
environment variable to the location of the site script.  A warning: not all `configure'
scripts look for a site script.

Defining Variables
==================

Variables not defined in a site shell script can be set in the environment passed to
`configure'.  However, some packages may run configure again during the build, and the
customized values of these variables may be lost.  In order to avoid this problem, you
should set them in the `configure' command line, using `VAR=value'.  For example:

     ./configure CC=/usr/local2/bin/gcc

causes the specified `gcc' to be used as the C compiler (unless it is overridden in the
site shell script).

Unfortunately, this technique does not work for `CONFIG_SHELL' due to an Autoconf bug.
Until the bug is fixed you can use this workaround:

     CONFIG_SHELL=/bin/bash /bin/bash ./configure CONFIG_SHELL=/bin/bash

`configure' Invocation
======================

`configure' recognizes the following options to control how it operates.

`--help'
`-h'
     Print a summary of all of the options to `configure', and exit.

`--help=short'
`--help=recursive'
     Print a summary of the options unique to this package's `configure', and exit.  The
     `short' variant lists options used only in the top level, while the `recursive'
     variant lists options also present in any nested packages.

`--version'
`-V'
     Print the version of Autoconf used to generate the `configure' script, and exit.

`--cache-file=FILE'
     Enable the cache: use and save the results of the tests in FILE, traditionally
     `config.cache'.  FILE defaults to `/dev/null' to disable caching.

`--config-cache'
`-C'
     Alias for `--cache-file=config.cache'.

`--quiet'
`--silent'
`-q'
     Do not print messages saying which checks are being made.  To suppress all normal
     output, redirect it to `/dev/null' (any error messages will still be shown).

`--srcdir=DIR'
     Look for the package's source code in directory DIR.  Usually `configure' can
     determine that directory automatically.

`--prefix=DIR'
     Use DIR as the installation prefix.  *note Installation Names::
     for more details, including other options available for fine-tuning
     the installation locations.

`--no-create'
`-n'
     Run the configure checks, but stop before creating any output files.

`configure' also accepts some other, not widely useful, options.  Run `configure --help'
for more details.