+Copyright (C) 1994, 1995, 1996, 1999, 2000, 2001, 2002 Free Software
+ This file is free documentation; the Free Software Foundation gives
+unlimited permission to copy, distribute and modify it.
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, a file
-`config.cache' that saves the results of its tests to speed up
-reconfiguring, and a file `config.log' containing compiler output
-(useful mainly for debugging `configure').
+you can run in the future to recreate the current configuration, and a
+file `config.log' containing compiler output (useful mainly for
+ 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
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 at some point `config.cache'
-contains results you don't want to keep, you may remove or edit it.
+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
- The file `configure.in' is used to create `configure' by a program
-called `autoconf'. You only need `configure.in' if you want to change
-it or regenerate `configure' using a newer version of `autoconf'.
+ The file `configure.ac' (or `configure.in') is used to create
+`configure' by a program called `autoconf'. You only 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:
Some systems require unusual options for compilation or linking that
-the `configure' script does not know about. You can give `configure'
-initial values for variables by setting them in the environment. Using
-a Bourne-compatible shell, you can do that on the command line like
- CC=c89 CFLAGS=-O2 LIBS=-lposix ./configure
+the `configure' script does not know about. Run `./configure --help'
+for details on some of the pertinent environment variables.
+ You can give `configure' initial values for configuration parameters
+by setting variables in the command line or in the environment. Here
-Or on systems that have the `env' program, you can do it like this:
- env CPPFLAGS=-I/usr/local/include LDFLAGS=-s ./configure
+ ./configure CC=c89 CFLAGS=-O2 LIBS=-lposix
+ *Note Defining Variables::, for more details.
Compiling For Multiple Architectures
the `configure' script. `configure' automatically checks for the
source code in the directory that `configure' is in and in `..'.
- If you have to use a `make' that does not supports the `VPATH'
-variable, you have 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
+ If you have to use a `make' that does not support the `VPATH'
+variable, you have 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.
Specifying the System Type
- There may be some features `configure' can not figure out
-automatically, but needs to determine by the type of host the package
-will run on. Usually `configure' can figure that out, but if it prints
-a message saying it can not guess the host type, give it the
-`--host=TYPE' option. TYPE can either be a short name for the system
-type, such as `sun4', or a canonical name with three fields:
+ 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:
-See the file `config.sub' for the possible values of each field. If
+where SYSTEM can have one of these forms:
+ 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
+need to know the type.
- If you are building compiler tools for cross-compiling, you
+ If you are building compiler tools for cross-compiling, you
use the `--target=TYPE' option to select the type of system they will
-produce code for and the `--build=TYPE' option to select the type of
-system on which you are compiling the package.
+ 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'.
`CONFIG_SITE' environment variable to the location of the site script.
A warning: not all `configure' scripts look for a site script.
+ 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
+will cause the specified gcc to be used as the C compiler (unless it is
+overridden in the site shell script).
`configure' recognizes the following options to control how it
- Use and save the results of the tests in FILE instead of
- `./config.cache'. Set FILE to `/dev/null' to disable caching, for
Print a summary of the options to `configure', and exit.
+ Print the version of Autoconf used to generate the `configure'
+ Enable the cache: use and save the results of the tests in FILE,
+ traditionally `config.cache'. FILE defaults to `/dev/null' to
+ Alias for `--cache-file=config.cache'.
Look for the package's source code in directory DIR. Usually
`configure' can determine that directory automatically.
- Print the version of Autoconf used to generate the `configure'
+`configure' also accepts some other, not widely useful, options. Run
+`configure --help' for more details.
-`configure' also accepts some other, not widely useful, options.