+@node Declarations, Per-host, Configure Variables, configure.in
+@subsection For each invocation
+
+@cindex Declarations section
+
+@code{configure} sources the entire shell script fragment from the start
+of @file{configure.in} up to a line beginning with @samp{# Per-host:}
+immediately after parsing command line arguments. The variables
+@code{srctrigger} and @code{srcname} @emph{must} be set here.
+
+You might also want to set the variable @code{configdirs} here.
+
+@node Per-host, Per-target, Declarations, configure.in
+@subsection For each host
+@cindex per-host section
+@cindex host shell-script fragment
+
+The per-host section of @file{configure.in} starts with the line that begins
+with @samp{# Per-host:} and ends before a line beginning with
+@samp{# Per-target:}. @code{configure} sources the per-host section once for
+each host.
+
+This section usually contains a big case statement using the variables
+@samp{host_cpu}, @samp{host_vendor}, and @samp{host_os} to determine
+appropriate values for @samp{host_makefile_frag} and @samp{files},
+although @samp{files} is not usually set here. Usually, it is set
+at the end of the per-target section after determining the names of the
+target specific configuration files.
+
+@node Per-target, Post-target, Per-host, configure.in
+@subsection For each target
+@cindex per-target section
+@cindex target shell-script fragment
+
+The per-target section of @file{configure.in} starts with the line that
+begins with @samp{# Per-target:} and ends before the line that begins
+with @samp{# Post-target:}, if there is such a line. Otherwise the
+per-target section extends to the end of the file. @code{configure} sources
+the per-target section once for each target before building any files,
+directories, or links.
+
+This section usually contains a big case statement using the variables called
+@samp{target_cpu}, @samp{target_vendor}, and @samp{target_os} to determine
+appropriate values for @samp{target_makefile_frag} and @samp{files}.
+The last lines in the per-target section normally set the variables
+@code{files} and @code{links}.
+
+@node Post-target, Example, Per-target, configure.in
+@subsection After each target
+
+The post-target section is optional. If it exists, the post-target
+section starts with a line beginning with @code{# Post-target:} and
+extends to the end of the file. If it exists, @code{configure} sources this
+section once for each target after building all files, directories, or
+links.
+
+This section is seldom needed, but you can use it to edit the Makefile
+generated by @code{configure}.
+
+@node Example, , Post-target, configure.in
+@subsection An example @file{configure.in}
+@cindex example @file{configure.in}
+@cindex sample @file{configure.in}
+@cindex Bison @file{configure.in}
+
+Here is a small example of a @file{configure.in} file.