6.3.2.1 Scripts Used by configure

configure uses some other scripts to help in its work:

• The standard GNU config.sub and config.guess files, kept in the top level directory, are used. FIXME: when is the config.guess file in the gcc directory (that just calls the top level one) used?
• The file config.gcc is used to handle configuration specific to the particular target machine. The file config.build is used to handle configuration specific to the particular build machine. The file config.host is used to handle configuration specific to the particular host machine. (In general, these should only be used for features that cannot reasonably be tested in Autoconf feature tests.) See The config.build; config.host; and config.gcc Files, for details of the contents of these files.
• Each language subdirectory has a file language/config-lang.in that is used for front-end-specific configuration. See The Front End config-lang.in File, for details of this file.
• A helper script configure.frag is used as part of creating the output of configure.