The choices and options available at configuration time generally have valid defaults, but the defaults do not cover all cases. The choices available include install locations, build directories, host, target, and local conventions.
configure what will source will
be built
configure what the source will
target
Using the default configuration, make install creates a
single tree of files, some of which are programs. The location of this
tree is determined by the value of the variable prefix. The
default value of prefix is `/usr/local'. This is
often correct for native tools installed on only one host.
In the default configuration, all files are installed in subdirectories
of `/usr/local'. The location is determined by the value of
the configure variable prefix; in turn, this determines the
value of the Makefile variable of the same name (prefix).
You can also set the value of the Makefile variable prefix
explicitly each time you invoke make if you are so inclined; but
because many programs have this location compiled in, you must specify
the prefix value consistently on each invocation of make,
or you will end up with a broken installation.
To make this easier, the value of the configure variable
prefix can be set on the command line to configure
using the option -prefix=.
By default, host dependent files are installed in subdirectories of
`exec_prefix'. The location is determined by the value of the
configure variable exec_prefix, which determines the value of
the Makefile variable exec_prefix. This makes it simpler to install
for a single host, and simplifies changing the default location for the
install tree; but the default doesn't allow for multiple hosts to
effectively share host independent files.
To configure so that multiple hosts can share common files, use something like:
configure host1 -prefix=/usr/gnu -exec_prefix=/usr/gnu/H-host1 make all info install install-info clean configure host2 -prefix=/usr/gnu -exec_prefix=/usr/gnu/H-host2 make all info install install-info
The first line configures the source for host1 to place host specific programs in subdirectories of `/usr/gnu/H-host1'.
The second line builds and installs all programs for host1, including both host independent and host specific files.
The third line reconfigures the source for host2 to place host specific programs in subdirectories of `/usr/gnu/H-host2'.
The fourth line builds and installs all programs for host2. Host specific files are installed in new directories, but the host independent files are installed on top of the host independent files installed for host1. This results in a single copy of the host independent files, suitable for use by both hosts.
During any install, a number of standard directories are created. Their
names are determined by Makefile variables. Some of the
defaults for Makefile variables can be changed at configure time using
command line options to configure. For more information on the
standard directories or the Makefile variables, please refer to
standards.text.
Note that configure does not create the directory srcdir
at any time. srcdir is not an installation directory.
You can override all makefile variables on the command line to
make. (See section `Overriding Variables' in Make.) If you do so, you will need to specify the
value precisely the same way for each invocation of make, or you
risk ending up with a broken installation. This is because many
programs have the locations of other programs or files compiled into
them. If you find yourself overriding any of the variables frequently,
you should consider site dependent Makefile fragments. See also
section Adding site info.
During make install, a number of standard directories are
created and populated. The following Makefile variables define them.
Those whose defaults are set by corresponding configure variables
are marked "Makefile and configure".
-prefix= command line option to
configure. (section Invoking.) The default value for
prefix is `/usr/local'.
bindir depends on prefix;
bindir is normally changed only indirectly through prefix.
The default value for bindir is `$(prefix)/bin'.
-exec_prefix= option to configure.
(See also section Invoking.) The default value for exec_prefix is
`$(prefix)'.
libdir depends on prefix; libdir is normally
changed only indirectly through prefix. The default value for
libdir is `$(prefix)/lib'.
man format documentation ("man pages"). The
default value for mandir depends on prefix;
mandir is normally changed only indirectly through prefix.
The default value for mandir is `$(prefix)/man'.
man1dir, man2dir, etc.
They name the specific directories for each man page section. For
example, man1dir holds `emacs.1' (the man page for the emacs
program), while man5dir holds `rcsfile.5' (the man page
describing the rcs data file format). The default value for any
of the manNdir variables depends indirectly on
prefix, and is normally changed only through prefix. The
default value for manNdir is
`$(mandir)/manN'.
configure. The GNU coding standards
do not call for man1ext, man2ext, so the intended use for
manext is apparently not parallel to mandir. Its use is
not clear. (See also section Extensions to the GNU coding standards.)
infodir depends indirectly on prefix; infodir is
normally changed only through prefix. The default value for
infodir is `$(prefix)/info'.
info or man. The default value for docdir
depends indirectly on prefix; docdir is normally changed only
through prefix. The default value for docdir
is `$(datadir)/doc'. This variable is an extension to
the GNU coding standards. (See also section Extensions to the GNU coding standards.)
libdir. The default value for includedir depends on
prefix; includedir is normally changed only indirectly
through prefix. The default value for includedir is
`$(prefix)/include'.
Normally, configure builds a `Makefile' and symbolic links
in the same directory as the source files. This is the typical
UN*X way to build programs, but it has limitations. For instance,
using this approach, you can only build for one host at a time.
We refer to the directories where configure builds a
Makefile as the build directories or sometimes as
objdir because these are the directories in which make
will build object files, among other things.
The default build directory is the same as the source directory. You can use a different build directory with a sequence like the following:
mkdir builddir cd builddir configure host -srcdir=sourcedirectory
where builddir is the directory where you wish to build, host is the host for which you want to build, and sourcedirectory is the directory containing the source files.
If you were to do this twice with different values for builddir
and host, then you could make for both at the same time.
The arguments to configure are hosts. By host we
mean the environment in which the source will be compiled. This need
not necessarily be the same as the physical machine involved,
although it usually is.
For example, if some obscure machine running an operating system other than UN*X had the GNU POSIX emulation libraries available, it would be possible to configure most GNU source for a POSIX system and build it on the obscure host.
For more on this topic, see section `Host Environments' in On Configuring Development Tools.
For building native development tools, or most of the other GNU tools, you need not worry about the target. The target of a configuration defaults to the same as the host.
For building cross development tools, please see section `Building Development Environments' in On Configuring Development Tools.
If you find that a tool does not get configured to your liking, or if
configure's conventions differ from your local conventions, you
should probably consider site specific Makefile fragments. See also
section Adding site info.
These are probably not the right choice for options that can be set from
the configure command line or for differences that are host or
target dependent.